WO2004019051A1 - 磁気センサー - Google Patents
磁気センサー Download PDFInfo
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- WO2004019051A1 WO2004019051A1 PCT/JP2003/001543 JP0301543W WO2004019051A1 WO 2004019051 A1 WO2004019051 A1 WO 2004019051A1 JP 0301543 W JP0301543 W JP 0301543W WO 2004019051 A1 WO2004019051 A1 WO 2004019051A1
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- Prior art keywords
- magnetic sensor
- thin film
- magnetic
- harmonic
- polarization
- Prior art date
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C13/00—Digital stores characterised by the use of storage elements not covered by groups G11C11/00, G11C23/00, or G11C25/00
- G11C13/04—Digital stores characterised by the use of storage elements not covered by groups G11C11/00, G11C23/00, or G11C25/00 using optical elements ; using other beam accessed elements, e.g. electron or ion beam
- G11C13/06—Digital stores characterised by the use of storage elements not covered by groups G11C11/00, G11C23/00, or G11C25/00 using optical elements ; using other beam accessed elements, e.g. electron or ion beam using magneto-optical elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/032—Measuring direction or magnitude of magnetic fields or magnetic flux using magneto-optic devices, e.g. Faraday or Cotton-Mouton effect
- G01R33/0325—Measuring direction or magnitude of magnetic fields or magnetic flux using magneto-optic devices, e.g. Faraday or Cotton-Mouton effect using the Kerr effect
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/095—Magnetoresistive devices extraordinary magnetoresistance sensors
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/10532—Heads
- G11B11/10541—Heads for reproducing
- G11B11/10543—Heads for reproducing using optical beam of radiation
- G11B11/10547—Heads for reproducing using optical beam of radiation interacting with the magnetisation of an intermediate transfer element, e.g. magnetic film, included in the head
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/1278—Structure or manufacture of heads, e.g. inductive specially adapted for magnetisations perpendicular to the surface of the record carrier
Definitions
- the present invention relates to a magnetic sensor, and particularly to a magneto-optical disk and a hard disk device.
- This relates to a magnetic sensor element using a second harmonic that enables the spin information embedded in a solid such as a (HDD) to be read (reproduced) with high sensitivity and high spatial resolution.
- a solid such as a (HDD)
- the information recorded on the magneto-optical disk is reproduced by using the reflected light force effect, which is a magneto-optical effect.
- FIG. 1 is an explanatory diagram of the principle of reproduction of such a conventional magneto-optical disk.
- 1 is a semiconductor laser
- 2, 4, and 5 are lenses
- 3 is a polarizer
- 6 is an analyzer
- 7 is a photodiode
- 8 is incident light
- 9 is reflected light
- 10 is a perpendicular magnetic recording film. Is shown.
- the principle of reproduction of a magneto-optical disk is that the plane of polarization of reflected light 9 rotates with respect to the plane of polarization of incident light 8 due to the force effect.
- the rotation angle of the polarization plane of the reflected light 9 is read to reproduce the memory.
- the rotation angle at this time becomes largest when the direction of magnetization is parallel to the direction of travel of light.
- a material having magnetization perpendicular to the surface of the medium is desired for the recording film.
- the perpendicular magnetic layer increases the surface density and enables high-density recording. For this reason, this perpendicular magnetic recording system will become the mainstream in the future.
- the memory capacity of the magneto-optical disk depends on the spot size of the semiconductor laser used for reproduction.
- the reproduction wavelength of an ordinary semiconductor laser is about 0.78 wm to 0.65 m. Therefore, the size of the magnetization is limited to about the reading wavelength in terms of reading accuracy. This limits the recording capacity and is the biggest issue to be solved in the future.
- inventions such as the MSR (magnetically induced super-resolution) method have been made. By using this, it is becoming possible to read even the magnetization size which is about half of the reproduction wavelength of a normal semiconductor laser. According to K. Shono [J. Magn. So c. Jpn. 19, Supple e.
- TMR tunnel magnetic toresisti ve
- the diameter of the reading element is a few mm at the prototype stage (So lineta l., Science, vo l. 289, p p. 1 530-1532, Sep. 2000 ) And 0.lm (1000 People) Since the following readings have yet to be made, they are still far from realizable for practical use. Disclosure of the invention
- the first object of the present invention is to make it possible to reproduce magnetic recording even if the size of the recorded magnetization is as small as 100, 100, or several persons lattice size. It was done. As a result, the memory capacity of magneto-optical disks and HDDs will increase dramatically.
- This method is fundamentally different from the conventional Kerr rotation mechanism and the magnetoresistive mechanism, and uses the rotation of the polarization plane of the second harmonic of the reflected light with respect to the incident light based on the nonlinear optical response theory of the asymmetry of the magnetic material. To provide a magnetic sensor.
- the second purpose is a magnetic sensor that does not limit the incident light intensity, that is, a magnetic sensor that can directly read the magnetization recorded on the magneto-optical disk without irradiating the magneto-optical disk with the incident light itself. It is to provide a sensor. This is to unnecessarily raise the temperature of the recording medium to a high temperature during reproduction, and to avoid the risk that the recording medium is heated to a temperature higher than the magnetization transition temperature.
- a magnetic field from a magneto-optical disk can be detected by injecting a semiconductor laser beam into a magnetic sensor element and detecting a second harmonic signal which is an output from the element. Becomes possible. Therefore, unlike the case where the conventional force effect is used as the reproducing method, it is possible to reproduce the information written on the magneto-optical disk without directly irradiating the magneto-optical disk with light.
- a third object is to irradiate a semiconductor laser element for generating a second harmonic to one element of a magnetic sensor that reads magnetization recorded on a magneto-optical disk.
- Use a magnetic sensor that has a sufficient S / N ratio To provide.
- the rotation angle of the polarization plane obtained from the magnetic sensor element is several ten times to several hundred times larger than the rotation angle of the polarization plane obtained by the conventional Kerr effect (several degrees to several degrees). Because of the giant polarization rotation angle (several tens of degrees), a signal with a high S / N ratio can be obtained.
- the wavelength of the incident wavelength and the wavelength of the second harmonic are as short as 1/2. If a wavelength filter is used, a reflected wave component having the same wavelength as the incident wave can be easily removed, so that a second harmonic signal having a high S / N ratio can be obtained. This is also an advantage compared with the conventional car rotation.
- the magnetic recording can be reproduced even if the recorded magnetization size is very small, and the recording was performed on the magneto-optical disk without irradiating the magneto-optical disk with the incident light itself.
- An object of the present invention is to provide a magnetic sensor capable of directly reading magnetization and obtaining a signal having a high S / N ratio.
- a magnetic sensor element having a spatially asymmetric interface structure disposed on an object having spin information, wherein one solid material constituting the interface is a magnetic material;
- the laser light irradiation means emits laser light having a frequency of ⁇ to the magnetic sensor element from the laser light irradiation means, thereby emitting the laser light from the magnetic sensor element.
- the spin information of an object having spin information is read out by changing the rotation angle of the polarization plane of the second harmonic having a frequency of 2 ⁇ .
- At least one magnetic material of the magnetic sensor element has an interface made of a ferromagnetic (including ferrimagnetic) material. It is characterized by having a structure.
- At least one material of one element of the magnetic sensor is a ferromagnetic (including ferrimagnetic) thin film material, It is characterized by using a multilayer thin film material in which the interface is composed of a plurality of thin film materials.
- at least one of the plurality of thin film materials is a transition metal or a transition metal oxide film.
- the easy magnetization axis and the polarization axis are orthogonal to each other in at least one thin film or crystal flake of the magnetic sensor element in order to generate the second harmonic. It is characterized by using a material.
- an oxide of Fe and an oxide of Fe as a material in which the axis of easy magnetization and the axis of polarization of the magnetic sensor element are orthogonal to each other. It is characterized by using a Fe oxide thin film.
- an SrTi 3 crystal is used as a substrate material for supporting a plurality of thin film materials of the magnetic sensor element. It is characterized by the following.
- the present invention is intended to realize a magnetic sensor as a recording / reproducing element which is indispensable for realizing a super-giant magneto-optical disk and HDD of several terabits (Tb) psi (persquare inch) region. Information is stored
- Tb terabits
- psi persquare inch
- the minimum configuration requirement of this magnetic sensor is that at least one is made of a ferromagnetic material (including a ferromagnetic material) (claim 2).
- the material other than one ferromagnetic material is not limited to a solid and may be a gas. If an interface composed of two types of materials can be defined, the polarization plane of the second harmonic of the reflected light (transmitted light) with respect to the incident light rotates with respect to the polarization plane of the incident light, and the magnetic field composed of several types of thin films A similar effect is produced with the sensor (claim 3).
- the magnetic material may be a transition metal or a transition metal oxide (Claim 4), or may be an Mn oxide compound exhibiting various magnetisms (Claim 5).
- Claim 10 shows the geometrical arrangement of the magnetic sensor.
- Claims 11 to 17 show polarized magnetic (thin film) materials capable of forming a magnetic sensor using the second harmonic.
- Claims 18 and 19 show the materials for the protective film or substrate of these multilayer films. These matrixes are identified as suitable materials with few misfits in terms of the thin film material being considered and the lattice constant.
- a magnetic sensor capable of reading out spin information embedded in a solid.
- an element which can reproduce even if the storage magnetic area is a few hundred or less than 100 or a very small area.
- This element can also be used as a reading device for a hard disk drive (HDD). With this regenerative element, Allows storage capacity to be raised to the 100 Gbpsi range.
- FIG. 1 is an explanatory view of the principle of reproduction of a conventional magneto-optical disk.
- FIG. 2 is a principle diagram of a magnetic sensor using the first harmonic of the present invention.
- FIG. 3 is a sectional view showing the structure of one element of the superlattice L SMO magnetic sensor of the present invention.
- FIG. 4 is a diagram showing an arrangement relationship between a superlattice L SMO magnetic sensor element of the present invention and a laser beam.
- FIG. 5 is a diagram showing the rotation characteristics of the polarization plane of the first harmonic of the superlattice LSM • magnetic sensor element of the present invention.
- FIG. 6 is a diagram showing the incident angle dependence of the polarization plane of the second harmonic of the superlattice LSM0 magnetic sensor element of the present invention.
- FIG. 7 is a diagram showing the temperature and magnetization dependence of the polarization plane of the second harmonic of the superlattice L SMO magnetic sensor element of the present invention.
- FIG. 8 is a diagram showing the positional relationship between G a F e 0 3 crystal structure of the magnetic sensor-element and the laser beam of the present invention.
- FIG. I is a principle diagram of a magnetic sensor using the first harmonic of the present invention.
- 101 is a perpendicular magnetic recording film (an object having spin information: a recording medium)
- 102 is a sensor element
- 103 is a magnetic material
- 104 is a laser beam having a frequency of ⁇
- 105 is a second harmonic having a frequency of 1 ⁇ .
- a laser beam 104 having a frequency ⁇ is incident on the sensor element 102 at an incident angle ⁇ .
- the material forming the sensor element 102 is the magnetic body 103.
- the magnetic material 103 is directed downward (data 0) or upward in the perpendicular magnetic recording film 101.
- the +-magnetic field (magnetic flux density B) generated from the magnetization of (Data 1), and the spin direction of the magnetic domain is downward; the X direction (in the case of ferromagnetic material 103), or the magnetic domain Spin direction is upward.
- a second harmonic 105 having a frequency of 2 ⁇ is generated, and the plane of polarization of the second harmonic 105 rotates once.
- the spin direction of the perpendicular magnetic recording film 101 can be detected. Therefore, it functions as one element 102 of the magnetic sensor.
- the present invention focused on this principle and constructed a magnetic sensor.
- this principle can be used as a monitor of the spin state of the interface because it is sensitive to the interface, and furthermore, it utilizes the fact that the spin direction of this interface reacts to the magnetic field generated from the magnetic layer forming the memory.
- the magnetic sensor using the first harmonic only needs to form an essentially asymmetric structure, in principle, it is only necessary to form an interface of several persons. That is, since the interface of several persons is a factor that limits the spatial resolution of the magnetic sensor, it is possible to read the magnetization of several persons. Actually, it depends on the flatness of the interface and the film thickness for forming a thin film as shown in the embodiment. However, the spatial resolution enables reading in a very small area in a very short time.
- the present invention shows that this effect is enhanced when the material constituting these elements has an electric polarization ⁇ .
- the polarization ⁇ faces the ⁇ -axis and the magnetic field is in the X-axis direction
- a second harmonic is generated when the electric field vector ⁇ of the incident light has a y-direction component.
- the secondary susceptibility ⁇ (2) is
- X yyy (2) Ct MXPZ P yyy (2) occurs due to the presence of Pz. This indicates that polarized materials can enhance these effects.
- the rotation angle of the plane of polarization is proportional to the magnitude of the generated magnetization. Since the magnitude of this magnetization is almost proportional to the external magnetic field at a weak magnetic field, it depends on the magnetic field strength at which the memory magnetization is generated.
- FIG. 3 is a sectional view showing the structure of an LSM0 magnetic sensor element having a superlattice structure according to the present invention.
- a (100) plane of SrTi 3 (abbreviation: STO) 201 was used as a substrate.
- S r Mn0 3 (abbreviation; LSMO) 202 the stacking 1 0 molecule layer.
- LaAlO 3 (abbreviation: LAO) 203 is laminated on it, and STO 204 is laminated on 3 molecular layers.
- the film thickness of each single layer is 3.824 for LSMO 202, 3.750 for LAO 203, and 3.905 for ST ⁇ 204.
- the 10 unit is 574.55 A. These molecular layers were laminated by a laser ablation method. The number of layers was determined by RHEED (reflection high energy electron diffraction) observation. The use of ST0201 for the substrate is intended to reduce the misfit of the lattice constant with the film laminated on top.
- LSMO 202 is a ferromagnetic film and has an in-plane magnetization facilitating axis.
- FIG. 4 is a diagram showing an arrangement of a superlattice L SMO magnetic sensor element of the present invention and a laser beam.
- 301 indicates that the upper and lower interface structures of LSM ⁇ are different.
- Reference numeral 302 denotes an incident laser beam having a frequency of ⁇
- 303 denotes a second harmonic having a frequency of 2 ⁇ .
- the superlattice-structured magnetic sensor element shown in Fig. 3 has an asymmetric structure. In other words, focusing on one magnetic film L SM022, the upper film is LAO 203 and the lower film is STO film 204. At this time, the upper interface structure and the lower interface structure of L SMO 202 are arranged differently.
- the second harmonic generated from the upper interface and the second harmonic generated from the lower interface are reversed in phase with each other and erased. No harmonics 303 will occur. In other words, no I harmonic is generated at the interface where symmetry is preserved. Since the structure shown in the embodiment has asymmetry, the second harmonic 303 of p-polarized light is generated.
- the polarization plane of the second harmonic 303 is a composite wave of the p wave coming from the asymmetry and the s wave coming from the magnetization.
- the 10 basic units are stacked to increase the intensity signal of the second harmonic 303. If these laminated film units are transparent to the energy of the incident light 302, the signal intensity of the second harmonic 303 is expected to be large. In the embodiment, an incident energy of 1.55 eV was selected. Since the s-polarized light intensity of the second harmonic 303 is proportional to the magnetization intensity, the rotation angle of the polarized light depends on the magnetization intensity.
- FIG. 5 is a diagram showing the rotation characteristic of the polarization plane of the first harmonic of the superlattice LSM0 magnetic sensor element.
- the reference is + 0.35T, and ⁇ indicates the case of 0.35 ⁇ .
- magnetization was generated by applying an external magnetic field of 0.35 Tesla (0.35 ⁇ ) in each of the + and-directions, and the polarization angle of the second harmonic was measured.
- Figure 5 shows a measurement example of the polarization angle and the second harmonic (SHG) intensity at an incident energy of 1.55 eV, an incident angle of 13 °, and a sample temperature of 10K.
- B + 0.35T
- an analyzer should be placed on the output light side of the SHG to detect the intensity of the light coming out. This is the same as reading the "up spin” and "down spin” of the magnetization axis stored by one rotation of the magneto-optical force shown in FIG.
- the analyzer adopts the arrangement of the polarization plane inclined at 45 °, so that the signal intensity difference at 45 ° in Figs. 6 (c) and (d) is read, so that + B (45 ° ), The difference in SHG intensity at one B (45 °) will be seen.
- the signal strength changes about 50% of the maximum value of the SHG signal strength. Therefore, a rotation of the polarization angle of 33 ° is generated as a memory reproduction signal, which is a very large signal change, and a large reproduction signal can be obtained.
- FIG. 6 is a diagram showing the incident angle dependence of the polarization plane of the first harmonic of the superlattice LSM magnetic sensor element of the present invention.
- FIG. 6 (a) shows the incidence of one laser beam having a frequency ⁇ .
- FIG. 6B shows the polarization plane of the second harmonic when the angle ⁇ 1 is 26 °, and
- FIG. 6B shows the second plane when the incident angle ⁇ 2 of the laser beam with the frequency ⁇ is 13 °.
- FIG. 6 (d) is a diagram showing the rotation angle ( ⁇ and the SH intensity characteristic) of the polarization plane in the case of FIG. 6 (b).
- the laser beam 401 having a frequency ⁇ is incident.
- a second harmonic 402 having a frequency of 2 ⁇ is obtained, and
- a laser beam 501 having a frequency of 2 is incident, and a second harmonic 502 having a frequency of 2 ⁇ is obtained. .
- the rotation angle of this plane of polarization depends on the angle of incidence ⁇ (see the inset in Figure 6). In other words, the smaller the angle of incidence ⁇ , the greater the rotation of the plane of polarization. Therefore, it is advantageous that the incident angle ⁇ is small, but it is necessary to devise an optical arrangement. Unlike ordinary magnetization detection by Kerr rotation (Kerr effect), the energy of the emitted light is twice as large, so it can be separated by using an appropriate optical filter.
- FIG. 7 shows the temperature and magnetization dependence of the polarization plane of the second harmonic of the superlattice LS MO magnetic sensor element of the present invention.
- Figure (a) shows the case where the temperature is 10K (Kino +0.35 )
- Fig. 7 (b) shows the case where the temperature is 100 ⁇ (the difference between the temperature below +0.35 and the temperature of (The difference between 35 T is ⁇ 3.6 °)
- Fig. 7 () shows the difference between +0.35 and ⁇ -0.35 at a temperature of 300 K ⁇ 0.3.
- FIG. 7 (d) is a graph showing magnetic properties ( B / Mn) with respect to temperature (K). It can be seen that the rotation angle of the polarization plane of the second harmonic increases as the magnetization increases.
- the angle of incidence ⁇ was 13 °, and the polarization plane of the second harmonic was rotated 33 ° in ten directions of the magnetic field.
- the rotation angle is 0.35 ⁇ -350 OO e, and a relatively large external magnetic field is used due to the limitation of the experimental apparatus.
- This superlattice material has been shown to exhibit the same magnitude of magnetization in an external field as 100 OO e. That is, it is shown that a rotation angle of about 33 ° can be obtained even with an external magnetic field of 10 O O e.
- the current magneto-optical system that reads one rotation per force has sufficient accuracy industrially to read a rotation of about 0.1 °. If the leakage magnetic field from the perpendicular magnetization film is 1 ⁇ e, the rotation angle of the polarization plane of the first harmonic is about 0.3 °. This indicates that the identification can be performed with sufficient industrial accuracy.
- this superlattice is 575 as shown in Fig. 3, a minimum magnetization size of about 575A is possible.
- the signal processing technology is advanced, and it is possible to reduce the size of about 300 people to about half. Thus, it is possible to detect even the magnetization size of several hundred persons. In order to further improve the detection capability of a minute size, this unit may be reduced. In principle, it is possible to detect even a single layer of L SMO. There is a possibility that it has a very small size detection capability on the order of Angstrom.
- the temperature shown in this example is 10 K, if a material having a sufficiently high ferromagnetic transition temperature is used as the magnetic material and the superlattice structure is used, the magnetic sensor using the second harmonic operates sufficiently at room temperature. I do.
- a F e 0 3 orthorhombic crystal as a magnetic sensor element.
- This crystal has an orthorhombic crystal structure, and is Fc 2 ln 'in the space group classification. What is the axis of easy magnetization of this crystal? Axis and polarization axis have b-axis structure.
- Fig. 8 shows this crystal structure arrangement, the polarization direction of the incident light, and the SHG signal arrangement.
- FIG. 8 is a diagram showing an arrangement relationship between G a F e 0 3 crystal structure of the magnetic sensor-element and the laser beam of the present invention.
- 60 1 a magnetic sensor element comprising a GaF e0 3 orthorhombic crystal
- the laser first light composed of several omega vibrations 602, 603 is a second harmonic wave composed of several 2 omega vibration.
- the magnetic property of G a Fe 3 indicates ferrimagnetism.
- the transition temperature at this time is 110 K.
- the temperature dependency of GaFe 3 M of GaFe 3 is shown by the solid line in FIG. 9 (d).
- Figure 9 is a case of incident energy 1. 5 5 eV, s-polarized incident light angle 26 ° in G a F e 0 3 magnetic sensor-element of the present invention, SHG intensity and polarization plane ferrimagnetic transition temperature T c ( 2K (Fig. 9 (c)), 180K just below Tc (Fig. 9 (b)), and 100K (Fig. 9 (a)) sufficiently lower than Tc. It is a measurement result of.
- ⁇ 80 ° was obtained.
- the relationship between the rotation angle and the temperature is indicated by ⁇ in Fig. 9 (d). This dependence shows good agreement with the tendency of the magnetization curve of GaFeC, and the rotation angle of the polarization plane shows good agreement with the magnetic susceptibility of this magnetic sensor.
- Example 1 As shown in Example 1, a 45 ° polarizer is actually inserted on the SHG signal side to read the direction of the magnetic field. If it is about 180K, the output intensity of the polarizer can change by 100% of the maximum intensity of SHG.
- the actual polarization rotation angle depends on the magnetic field intensity generated from the magnetization of the memory, and the rotation angle is small. 03001543 Therefore, the higher the ability to rotate sensitively to a magnetic field, the better.
- the G a F e 0 3 crystals are produced by the floating zone melting method (Japanese Patent Application No. 200 2- 2 347 08) o
- the Ga 2 -X F ex 0 by heating the tip of the sample rod composed of Ga 2 -XF ex 0 3 arranged vertically and the confocal heat source in a gas atmosphere, the Ga 2 -X F ex 0
- the method is characterized in that a single crystal of Ga 2 XF ex ⁇ 3 having an orthorhombic crystal structure is produced by a floating melting zone method in which a floating melting zone is formed between the tips of a sample rod made of 3 .
- This example is a single crystal flake. At present it is F i e 1 d
- I on Be am (FIB) device If an I on Be am (FIB) device is used, it is possible to take out a crystal piece of 100 ⁇ m mouth with a film thickness of about 100 A and set it with its orientation kept. In other words, it is possible to detect a small magnetization size of about several hundred people.
- FIB I on Be am
- the present invention is not limited to the above embodiments, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.
- a magnetic sensor element capable of detecting a fine magnetic domain structure in a region of several hundred A by a method different from the conventional one. Since this element can detect even a fine magnetic domain structure of several OA, the big problem of the data reproducing device in the magnetic recording device is solved. As a result, it is possible to provide a huge magnetic memory device in the terabit area, and to provide a huge memory suitable for information communication and optical computers.
- this sensor-one element is not limited to the practical use of only the reproducing device of the magnetic memory.
- a current is passed through a coil, a magnetic field is generated.
- the rotation of the polarization plane of the second harmonic can be easily controlled.
- a polarizer is inserted on the output side, it is possible to easily turn off the light ⁇ N — OFF, and it can be applied as a current control type optical switch element in an optical communication network. It is also possible to create a function as an element.
- an open / close sensor for example, a mobile phone
- the invention can be applied not only to magnetic memories but also to basic elements in a wide range of information networks.
- the magnetic sensor of the present invention has high sensitivity and high spatial resolution, and is particularly suitable as a device for reproducing magnetic memory. It is also applicable as a basic device related to optical communication.
Abstract
Description
Claims
Priority Applications (4)
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JP2004530516A JP4185968B2 (ja) | 2002-08-23 | 2003-02-14 | 磁気センサー |
AU2003211223A AU2003211223A1 (en) | 2002-08-23 | 2003-02-14 | Magnetic sensor |
EP03792617A EP1505404B1 (en) | 2002-08-23 | 2003-02-14 | Magnetic sensor |
US10/495,127 US7084624B2 (en) | 2002-08-23 | 2003-02-14 | Magnetic sensor |
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JP2002-243942 | 2002-08-23 | ||
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US (1) | US7084624B2 (ja) |
EP (1) | EP1505404B1 (ja) |
JP (1) | JP4185968B2 (ja) |
KR (1) | KR100813449B1 (ja) |
AU (1) | AU2003211223A1 (ja) |
WO (1) | WO2004019051A1 (ja) |
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JP2007034093A (ja) * | 2005-07-29 | 2007-02-08 | Japan Science & Technology Agency | 光学装置 |
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US7738217B2 (en) * | 2006-02-13 | 2010-06-15 | Hitachi Global Storage Technologies Netherlands B.V. | EMR magnetic head having a magnetic flux guide and a body formed at a tail end of a slider |
WO2009073736A1 (en) * | 2007-12-03 | 2009-06-11 | President And Fellows Of Harvard College | Spin based magnetometer |
US7881006B2 (en) * | 2008-02-08 | 2011-02-01 | Seagate Technology Llc | Long-term asymmetry tracking in magnetic recording devices |
US9348000B1 (en) * | 2012-12-20 | 2016-05-24 | Seagate Technology Llc | Magneto optic kerr effect magnetometer for ultra-high anisotropy magnetic measurements |
JP5995923B2 (ja) * | 2014-08-06 | 2016-09-21 | 古河電気工業株式会社 | 光ファイバ母材および光ファイバの製造方法 |
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WO1985001144A1 (en) * | 1983-09-05 | 1985-03-14 | Sony Corporation | Photomagnetic recording and reproducing apparatus having device for detecting direction of magnetization of magnetic recording medium |
Family Cites Families (8)
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FR2517831A2 (fr) * | 1981-12-04 | 1983-06-10 | Thomson Csf | Tete de mesure pour magnetometre et magnetometre comprenant une telle tete |
US5038103A (en) * | 1985-04-22 | 1991-08-06 | The United States Of America As Represented By The Secretary Of The Navy | Optical fiber magnetometer |
FR2621412B1 (fr) * | 1987-10-05 | 1990-09-14 | Bull Sa | Dispositif de lecture optique et d'ecriture magnetique d'un support d'informations |
DE69029048T2 (de) * | 1989-04-19 | 1997-03-20 | Hitachi Ltd | Magnetooptische Aufzeichnungs- und Wiedergabeverfahren, magnetooptische Speichervorrichtung |
CA2036890C (en) * | 1990-02-28 | 1996-02-13 | Hiroyuki Katayama | Magneto-optic recording disk and method of reproducing recorded signals |
US5784347A (en) * | 1995-02-13 | 1998-07-21 | Hitachi, Ltd. | Optical disk device having optical phase compensator |
US6134011A (en) * | 1997-09-22 | 2000-10-17 | Hdi Instrumentation | Optical measurement system using polarized light |
JP4382333B2 (ja) * | 2002-03-28 | 2009-12-09 | 株式会社東芝 | 磁気抵抗効果素子、磁気ヘッド及び磁気再生装置 |
-
2003
- 2003-02-14 AU AU2003211223A patent/AU2003211223A1/en not_active Abandoned
- 2003-02-14 KR KR1020047008369A patent/KR100813449B1/ko not_active IP Right Cessation
- 2003-02-14 US US10/495,127 patent/US7084624B2/en not_active Expired - Fee Related
- 2003-02-14 WO PCT/JP2003/001543 patent/WO2004019051A1/ja active Application Filing
- 2003-02-14 EP EP03792617A patent/EP1505404B1/en not_active Expired - Fee Related
- 2003-02-14 JP JP2004530516A patent/JP4185968B2/ja not_active Expired - Lifetime
Patent Citations (1)
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---|---|---|---|---|
WO1985001144A1 (en) * | 1983-09-05 | 1985-03-14 | Sony Corporation | Photomagnetic recording and reproducing apparatus having device for detecting direction of magnetization of magnetic recording medium |
Non-Patent Citations (2)
Title |
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KOOPMANS BERT ET AL.: "Observation of large kerr angles in the nonlinear optical response from magnetic multilayers", PHYSICAL REVIEW LETTERS, vol. 74, no. 18, 1 May 1995 (1995-05-01), pages 3692 - 3695, XP002977644 * |
See also references of EP1505404A4 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007034093A (ja) * | 2005-07-29 | 2007-02-08 | Japan Science & Technology Agency | 光学装置 |
JP4576629B2 (ja) * | 2005-07-29 | 2010-11-10 | 独立行政法人科学技術振興機構 | 光学装置 |
Also Published As
Publication number | Publication date |
---|---|
JPWO2004019051A1 (ja) | 2005-12-15 |
AU2003211223A8 (en) | 2004-03-11 |
US7084624B2 (en) | 2006-08-01 |
JP4185968B2 (ja) | 2008-11-26 |
KR100813449B1 (ko) | 2008-03-13 |
EP1505404A4 (en) | 2009-04-22 |
KR20050032023A (ko) | 2005-04-06 |
AU2003211223A1 (en) | 2004-03-11 |
EP1505404B1 (en) | 2011-01-12 |
US20050012937A1 (en) | 2005-01-20 |
EP1505404A1 (en) | 2005-02-09 |
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