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Magneto-optical Kerr effect enhancement in longitudinal and transversal configurations is systematically studied in one- and two-dimensional magnetoplasmonic crystals based on the nanostructured nickel films. Spectral dependences of magneto-optical effects demonstrate resonant features with the Fano-type lineshape in the spectral vicinity of the Wood's anomaly associated with excitation of surface magnetoplasmons in Voigt and Faraday configurations, respectively.

Magnetization-induced second harmonic generation was observed in magnetophotonic microcavities consisting of a ferromagnetic yttrium-iron garnet layer surrounded by nonmagnetic photonic crystals (Bragg reflectors). At resonance between the fundamental radiation and the microcavity mode in the geometry of polar magnetooptical Kerr effect, the polarization rotation for the second harmonic was found to be (18.5±0.5)°/μm for the fundamental radiation with a wavelength of 825 nm.

A novel reflective magnetooptic spatial light modulator has been fabricated and its dynamic switching testing was investigated. Improvements by a factor of three in pixel switching sensitivity and power consumption could be achieved by the use of a wedge-shaped drive line, compared to the use of a conventional reflective magnetooptic spatial light modulator. Simpler fabrication processes by a factor of two could also be achieved by the use of a drive line which covers most of the surface of the pixel, a non-rectangular channel and a unpatterned insulator layer.

An extremely flat transmission band for a forward volume spin wave (SW) propagating in an SW waveguide composed of yttrium iron garnet film and SW absorbers was obtained, using the finite integration technique. Three-dimensional analysis of the calculated results showed that the transmission ripples of the SWs propagating in the waveguide were caused by SW interference, especially that due to two standing waves originating from the waveguide edge–edge and the waveguide–antenna edge. To suppress these waves, SW absorbers composed of gold film were introduced and the resultant positions and shapes were investigated precisely. Hence, an extremely flat transmission band was obtained. The results of this study have potential application in the development of one- and two-dimensional magnonic crystals for integrated SW devices.

Three-dimensional magneto photonic crystals (3D-MPCs) are promising material for manipulating light in 3D space. In this study, we fabricated 3D-MPC that is filling the air-gap of opal photonic crystal with magnetic material by electroless plating. The electroless plating is an attractive film-forming method which provides magnetic material films on various substrates in aqueous solution at 24-90 °C. As magnetic material for filling the air-gap, maghemite (γ-Fe2O3) film was plated in opal photonic crystal. The plated maghemite film showed a Faraday rotation of 0.6 deg./μm at 440 nm and significantly lower absorption than magnetite. The plated opal showed photonic band gap and magneto-optic response. Faraday rotation of the plated opal was enhanced at the band edge. The photonic band gap and the Faraday rotation spectra were changed as a function of incident angle of light. Electroless plating of maghemite could be promising technique for fabricating 3D-MPCs.

This paper proposes a vibrational circuit breaker which cuts an electric and/or electronic circuit by vibration of acceleration more than a certain value. This structure consists of a fixed magnet, a moving magnet, and a fixed part of two ferromagnets/magnet. It works from on-state to off-state when the two ferromagnets separate. This vibrational circuit breaker has advantages: auto-detection, no battery, and simple structure.

Vacuum annealed polycrystalline cerium substituted yttrium iron garnet (CeYIG) films deposited by radio frequency magnetron sputtering on non-garnet substrates were used in nonreciprocal racetrack resonators. CeYIG annealed at 800°C for 30 min provided a large Faraday rotation angle, close to the single crystal value. Crystallinity, magnetic properties, refractive indices and absorption coefficients were measured. The resonant transmission peak of the racetrack resonator covered with CeYIG was non-reciprocally shifted by applying an in-plane magnetic field.

The swimming properties of a magnetic micro-machine with a spiral structure were examined experimentally and theoretically under very low Reynolds number conditions. It was demonstrated that the micro-machine could swim in a highly viscous fluid with a Reynolds number of 10-7. This result suggests that the micro-machine has a great potential for medical applications. It was found that the optimum blade shape of the micro-machine varied with the Reynolds number condition.

We have demonstrated a magneto-optical spatial light modulator in which functionality is realized by (i) heating up to Curie temperature ( T c ) magneto-optical elements (pixels) with a semiconductor laser and (ii) application of a switching magnetic field. The pixels were made of films of amorphous rare earth–transition metal compounds (TbFe films with T c =403 K and DyFe films with T c =343 K) having good magneto-optical responses for wavelengths from the visible spectral range. We have found that the magnetization direction of pixels can be modulated with a laser radiation density of 5 mJ/cm 2 and in a switching magnetic field of 15 Oe.

Elastically coupled magneto-electric (ME) elements were constructed and their fundamental properties were studied, so as to examine whether the elements exhibit considerable ME effect at room temperature. The elements had a hybrid structure, in which thin soft glass substrates with highly magnetostrictive amorphous FeCoSiB films were bonded on lead zirconate titanate (PZT) piezoelectric substrates. When a direct current (dc) voltage was applied to the element, large changes in the magnetic properties of the FeCoSiB film were observed. For example, by applying a dc voltage from -200 V to + 200 V, changes in magnetic permeability of the film reached about 1680%. It was also demonstrated that high-frequency impedance of the element was subject to change with a dc voltage applied to PZT layer. These unique characteristics of the present ME elements are considered to be very attractive for constructing smart actuators with a sensing function.

The swimming properties of spiral-type magnetic micromachines were analyzed theoretically by 2-dimensional finite volume. Good agreement between experimental and theoretical results was obtained. Swimming properties of micromachines depend strongly on the operational environment, including the flow field and machine structure. We analyzed the effect of machine shape on swimming properties. The optimum design of the blade shape was obtained by simulation. Based on optimum design, the micromachine was fabricated by stereolithography. Machine swimming agreed well with results.

A new type of laser probe for observation of surface-acoustic waves (SAWs) is presented. The probe operation is based on the knife-edge technique combined with an optical sampling method that employs a pulsed laser beam. The spatial resolution of the probe is 1.3 μm and its bandwidth is greater than 1 GHz. A highly nonlinear SAW involving 10 harmonics on single-crystal lithium-niobate (LiNbO3) plates has been studied at the input frequency 200 MHz. It is shown that the initially sinusoidal wave breaks into a train of pulses up to four per period with the evolution of time. The spectrum data were related to SAW harmonic generation studied previously under similar conditions. Head-to-head collision of two SAW wave packets of 500 ns duration has been studied. It was confirmed that the wave forms are preserved in the collision. In addition, the effect of nonlinear diffraction of a SAW driven by high input power levels was observed. The present probe is found to be a powerful tool for elucidation of SAW solitons.

A remote temperature sensing system was investigated for use, local such as inside the human body. The system was divided into a magnetic generating part, temperature sensing and temperature information generating part, and temperature information receiving part. A ferrite having a low Curie temperature was used in the temperature sensing part. To receive and transmit the temperature information effectively, LC resonance circuits were used in the system. The resonance frequency of 145 kHz to 220 kHz was varied in the range of 58°C to 66°C. From this experiment, we determined that temperature could be measured at the local site using this system.

The mmW band photonic Tamm states in 1D magnetophotonic crystals are studied. It is shown the possibility to manipulate the eigenfrequencies of such states by an external magnetic field. Our experimental results are in a good agreement with theoretical prediction.

A large enhancement of the Faraday rotation, which is associated with localized surface plasmon resonance (LSPR), was obtained in a sample with Au nanoparticles embedded in a Bi-substituted yttrium iron garnet (Bi:YIG) film. On a quartz substrate, Au nanoparticles were formed by heating an Au thin film, and a Bi:YIG film was then deposited on them. A sample containing the Au nanoparticles produced by 1000 °C heating showed a resonant attenuation with narrower bandwidth in the transmission spectrum than nanoparticles of other samples formed by low-temperature heating. The sharp resonant Faraday rotation angle was 4.4 times larger than the estimated intrinsic Bi:YIG film at the LSPR wavelength; the angular difference was 0.14°. A discrepancy in the bandwidth between the transmission attenuation and the resonant Faraday rotation is discussed.

We investigated an analogue modulation of magneto-optic spatial light modulator (MOSLM). For enhancement of the modulation from the voltage-driving MOSLM, magnetostriction and saturation magnetization of magnetic garnet films and piezoelectric constant of PZT films were investigated. The performance was expected to be improved by using Bismuth, Dysprosium and Aluminum substituted Yttrium Iron garnet, which effective magnetic field showed 20 times higher than Yttrium Iron garnet.

Spatial light modulator (SLM) is a real-time programmable device for modifying amplitude, phase or polarization of optical wave front by electrically controlled signals. Various types of SLMs with pixel arrays, such as a liquid crystal SLM, have been developed. Recently, SLMs have received much attention as a light modulator in holographic data storage which requires high speed SLMs for ensuring the high data transfer rate. In this field, the application of a magneto-optic SLM (MOSLM) is highly expected because of extremely fast pixel switching speed. The conventional MOSLM used a single crystal garnet with perpendicular magnetic anisotropy to switch as a binary depending on up and down magnetization. However, for an analog modulation in our concept, the direction of magnetization is gradually changed to in-plane direction, because the modulation is depending on the magnetization direction of the garnet film. A voltage driven MOSLM for analog modulation is developed using magnetostriction effect. Moreover, the MOSLM with a structure of a magnetophotonic crystal (MPC) is fabricated for the large enhancement of magneto-optical response. This report is about a current development of MOSLMs with magnetophonic crystal driven by a voltage.

The fundamental swimming properties of spiral-type magnetic micro-machines were investigated in detail by constructing four micro-machines with different structures. These micro-machines are able to swim in various liquids with kinematic viscosities ranging from 1.37 to 1000 mm2/s. This result suggests that the micro-machines have potential medical uses. In particular, they can swim against the stream in a liquid whose the velocity is comparable to the that of venous blood.

Amorphous FeCoSiB films with high saturation magnetostriction and excellent soft magnetic properties were studied to determine their strain sensitivity. The films were subjected to strain by bending of their substrates, which caused a change in the magnetic anisotropy of films via magnetoelastic coupling. The films exhibited a figure of merit F ≡ (θμ/θe)/μ (change in film permeability μ per unit of strain e) of 1.2 × 105, which is comparable to that of amorphous ribbons. To study the use of the magnetostrictive films as strain sensor elements, we prepared meander-patterned films by means of the photolithography and ion milling processes. The impedance change in the patterned films when strain was applied was measured in the frequency range from 1 MHz to 1 GHz. Reflecting the large value of F, the high-frequency impedance of the films was changed considerably: a change in impedance of 46% was observed at 100 MHz when a strain of 300 × 10-6 was applied. It is also demonstrated that, by using the strain-dependent impedance, a small strain of 1 × 10-7 can be detected by means of the film pattern.

The dysprosium substituted yttrium iron garnet (Dy:YIG) film was investigated because of high magnetstriction for operating voltage driven type magneto-optic spatial light modulators (V-MOSLMs). The fabricated Dy:YIG film had magnetostriction of 3.5 ppm, soft magnetic property, transmittance of 47 % and faraday rotation of -2.7 deg./μm at 532 nm wavelength. Furthermore, a reflection type one dimensional magneto photonic crystal (1D-MPC) by using the Dy:YIG film as a defect layer was fabricated for enhancement of Kerr rotation. In the case of the defect layer of 147 nm thick, a Kerr rotation angle was 15 times higher than the single layer at localized wavelength.

We demonstrate a newly developed magneto-photonic crystal (MPC) based magneto-optic spatial light modulator (MOSLM) which was designed to enhance the performance of a conventional MOSLM, and describe the preparation and fundamental properties of it. By introduction of MPC, the magneto-optical property of MOSLM was improved, and as driving properties, the saturation of brightness was shown around ±1 kOe and the change occurred from about ±300 Oe by external magnetic field. Also, we conformed that Kerr rotation angle of this device was varied by applying voltage to PZT film. The change of each pixel by applying voltage, however, could not be detected because of the small variation of brightness.

We have studied propagation of magnetostatic surface waves in yttrium iron garnet films with attached 1D periodic arrays of metal strips. For different experimental geometries and different designs of 1D periodic arrays of metal strips, propagation spectra of magnetostatic surface waves were measured and analyzed. We have shown a way to control propagation characteristics of magnetostatic surface waves by changing of electrical contact between periodic metal strips.

The field distribution of a light wave near a magnetic defect in a one-dimensional photonic crystal is analyzed. It is shown that, by properly varying the magnetic defect thickness or the parameters of the photonic crystal surrounding the defect, one can create a situation where the electric field of a light wave will be localized predominantly inside the magnetic layer or, conversely, in the immediate vicinity of the layer surface. This opens up possibilities for optimizing the Q factor of a magnetic microcavity in the presence of dissipation in the magnetic layer and, hence, for enhancing the linear and nonlinear magneto-optical effects. The possibility of separating the contributions from the surface and volume of the magnetic material to the nonlinear magnetooptical properties by properly varying the field distribution over the defect thickness is discussed.

The magnetic properties, especially magnetic softness and anisotropy, of highly magnetostrictive FeSiB amorphous films deposited on glass, silicon, Quartz, and LiNbO 3 substrates have been investigated. Although the films were deposited and annealed with the same process condition, there were quite large differences between the magnetic properties with variation of substrate. The prime factor defining the magnetic properties was defined with difference between the thermal expansions of film and substrate. When the film were deposited on the substrate with larger thermal expansion compared to the film, the soft magnetic properties became worse due to perpendicular anisotropy, which was coursed by compressive stress. For example, the coercive force of the film on LiNbO 3 substrate was about 30 Oe, while the coercive force of the film on silicon substrate was 0.3 Oe.

Fe-B amorphous alloy film was formed by means of contact plating method, in which Cu foils in contact with Al wires were used as substrates. Local battery configuration of the Cu foil anode and the Al wire cathode was responsible for film formation. The boron content in film was controlled from 0at% to 28at% by changing the KBH4 concentration in the bath. The bath temperature strongly affected the crystallographic structure of resultant films. Fe80B20 amorphous films required a bath temperature below 40°C. Film structure and composition also affected magnetic properties. Film coercivity below 17Oe was also observed.

Amorphous (a-) Fe-B alloy films for micro-magnetic device applications were fabricated by electrodeposition. It was found that an appropriate KBH4 concentration greater than 300mM and a bath temperature of less than 30°C were indispensable deposition conditions for obtaining a-Fe-B films with a B concentration exceeding 20at%. Furthermore, a-Fe-B films with low coercivity of less than 3.6 Oe and a large magnetostrictive constant of 26×10-6, which are thus comparable to sputtered a-Fe-B films, can be obtained by using a combined complex agent consisting of KNaC4H4O6 and (NH4)2SO4. ESCA measurements showed that about 80at% boron chemically bound with iron, but about 20at% boron combined with oxygen, because the electrodeposited films contain oxygen and carbon.

To obtain amorphous FeB-plated films with soft magnetization, the effect of a combined complex agent of potassium sodium tartrate (KNaC4H4O6 · 4H2O) and ammonium sulfate ( (NH4)2SO4) on the film properties was investigated. Soft magnetic films with coercivities of less than 4 Oe were obtained by using a bath composition of KNaC4H4O6 · 4H2O = 600mmol/L and (NH4)2SO4 = 80mmol/L. These soft films also exhibited large magnetostriction of 26 × 10-6, suggesting that the use of the combined complex agent is very effective for obtaining FeB amorphous films that have soft magnetic properties and large magnetostriction simultaneously. Change in composition of films along their thicknesses is considered to be responsible for the magnetic softening of FeB-plated films.

Magneto-electric (ME) elements were constructed by combining piezoelectric materials and magnetostrictive films. The fundamental properties of elements were studied, to determine whether the elements exhibit any considerable ME effect at room temperature. The elements had a hybrid structure, in which thin soft glass substrates with highly magnetostrictive amorphous FeCoSiB films were bonded on PZT piezoelectric substrates. When a dc voltage was applied to an element, large changes in the magnetic properties of the FeCoSiB film were observed: for example, when a dc voltage of between -200 V and +200 V was applied, the change in magnetic permeability of the film reached more than 1680%. These unique characteristics of the present ME elements are considered to be very attractive for constructing novel types of micromagnetic devices.

The vertical deposition technique and the RF-magnetron sputtering method were employed for fabrication of three-dimensional (3-D) magnetophotonic crystals, in which a bismuth-substituted yttrium-iron-garnet planar defect layer was sandwiched in between two opal thin films. Optical properties and structure of constitutive elements (opal thin films) were studied in detail. An evolution of optical response of a magnetophotonic heterostructure under preparation is presented

Magneto-optical transverse Kerr and Faraday effects are studied experimentally and theoretically in one-dimensional magnetophotonic crystals fabricated from a stack of four repetitions of layers of Bi-substituted yttrium iron garnet and SiO 2 layers. The results of theoretical calculations in the framework of modified matrices approach are consistent with the obtained experimental data with the exception of the one cusp at 480 nm in the transverse Kerr effect spectra. Possible mechanisms of this disagreement are discussed.

A magneto-optic spatial light modulator (MOSLM) driven by an electric field was fabricated, which is multiferroic device with magneto-optical garnet layer and piezoelectric PZT one. To control the direction of magnetization of the garnet layer, a stress field induced by PZT film was applied to the garnet layer. With an external magnetic field, the pixels of the MOSLM were switched. The driving current required for the magnetization switching was remarkably reduced to 500 nA, whose value was less than 1% of a driving current of the conventional current-driven MOSLM.

A magneto optic spatial light modulator (MO-SLM) for multiple-tone expression was fabricated by using in-plane magnetization of garnet film. By using Al substituted Bi:YIG film, magnetization curve was modified to suitable for multiple tone expression. Changing a driving current from 0 to 28 mA, we were able to change brightness of pixels in the line.

Bismuth-substituted yttrium iron garnet (Bi:YIG, Bi0.5Y2.5Fe5O12) films have been deposited with aerosol deposition method. We investigated the deposition rate, crystallinity, magnetic and optical properties dependent on carrier gas flow rate (0.5 L/min ∼ 8 L/min) and annealing temperature. With increasing annealing temperature, the crystallinity of Bi:YIG film was improved and the saturation magnetization increased to reach to 1.1 kG at 800°C. The magneto-optical effect, Faraday rotation, increased to 1.4 deg/μm by annealing at 700°C around the wavelength of 0.5 μm. The optical transmittance of the Bi:YIG film was also improved in visible region.

Amorphous iron-boron alloy films were fabricated by means of electroless plating, and the film formation mechanism was examined by studying the fabrication conditions. When a copper substrate in contact with an aluminum wire was used, the alloy films with considerably thick thicknesses were obtained. The local battery configuration of the copper substrate and the aluminum wire was considered to be responsible for the film formation. The boron content in the film increased monotonically from 0 at% to 28 at% with increasing the concentration of reducing agent (KBH 4 ). The bath temperature during the plating was found to be a significant parameter for governing the reduction power of the reducing agent and the resultant crystallographic structure of the films.

Previously we reported that rf-sputtered Bi 2 O 3 Fe 2 O 3 ABO 3 films (ABO 3 : Perovskite either of BaTiO 3 , PbTiO 3 , or PbZrO 3 ) have pronounced properties exhibiting magnetic as well as dielectric hysteresis loops simultaneously above room temperature for films with a restricted Fe 2 O 3 -concentration of about 70 at% after subject to thermal annealing at about 700°C. In the present study, we have prepared the same oxide films by the sol-gel method, where PbTiO 3 was chosen for ABO 3 . It was found that gel-coated films onto glass substrates and/or low-resistivity Si-wafers also possess the properties similar to those of rf-sputtered films. Microstructure of the films was examined by EXAFS measurement at the Fe-absorption edge. It may be concluded that a disordered oxide state having a random glass network structure is essential for realizing magnetic and dielectric ordered state, presumably caused by strong frustration in a glassy antiferromagnet.

Magneto-optical (MO) Faraday effect of discrete magnetic media was analyzed theoretically taking the structural randomness into account. The analysis was achieved using the random matrix approach by employing a model with a one-dimensional quasirandom array structure. The numerical results suggest that the MO Faraday spectra (MO-FS) of the discrete media with fine structures are determined uniquely without a significant influence from the structural randomness. In such a medium, the packing density of the magnetic materials and the medium thickness were found to be key parameters which govern the unique MO-FS of the discrete medium.

Magnetic and dielectric properties of films with the ternary oxide system Bi 2 O 3 -Fc 2 O 3 -PbTiO 3 , prepared by coating gel-solutions synthesizcd by the glycol-gel process on either glass plates or low rcsistivity Si-wafers were investigated. It was found that films with the Fe 2 O 3 -molar concentration around 70% exhibit ferromagnetic as well as ferroelectric behaviors simultaneously above room temperature retaining amorphous state from x-ray diffraction even after annealed at 700°C in air. The microstructure of the films was examined by EXAFS and was confirmed to be in a strongly disordered state. These pronounced properties are supposed to arise from a sort of excessively frustrated spin glasses.

In order to fabricate the thick ferrite films, electrophoretic deposition (EPD) of Ni-Zn ferrite fine particles in water dispersion mixtures was carried out at room temperature. It is shown that densely packed ferrite films with a thickness of 12/spl mu/m can be deposited via EPD at high deposition rate of 400nm/min from fine particles with a size of 10-30nm onto an ITO glass substrate. The particulate film exhibited soft magnetic properties almost the same as raw particles.

We report results on fabrication of three-dimensional (3D)-magnetophotonic crystals (MPCs) based on artificial opals. The opal samples composed of amorphous SiO/sub 2/ spheres were prepared using gravitational sedimentation. Quantitative evaluation of opal structure was done by fitting the (111) photonic bandgap by a Gaussian function. Changes in depth and width of the (111) photonic bandgap were observed after polishing less-ordered bottom side of the as-grown opal samples. To create 3D-MPCs, terbium gallium garnet was synthesized in an opal matrix.