Showing papers in "Journal of The Magnetics Society of Japan in 1991"
TL;DR: In this article, a method of high precision measurement of thin film permeability in the VHF frequency range has been developed, which can be used as a standard of the measuring system, and the results show that eddy current loss in the multilayer films cannot be suppressed even with spacers as thick as 2000A and the microcrystalline film exhibits relatively high loss in high frequency range.
Abstract: A method of high precision measurement of the thin film permeability in the VHF frequency range has been developed. Permeability of film in a high magnetic field can be predicted with very high accuracy. This permeability is used as a standard of the measuring system. Multilayer films with various spacer thicknesses and a FeZrN microcrystalline film were measured. Results show that eddy current loss in the multilayer films cannot be suppressed even with spacers as thick as 2000A and the microcrystalline film exhibits relatively high loss in the high frequency range.
50 citations
TL;DR: In this paper, the magnetic properties of Fe-Ta-Zr-N alloy films near the eutectic composition were studied and the structures and magnetic properties were changed by annealing or adjusting N2 partial pressure ratio.
Abstract: Microstructures and magnetic properties of Fe- (Ta, Nb, Zr)-N alloy films near the eutectic composition were studied. These new soft magnetic alloy films were prepared by N2 reactive sputtering. The structures and magnetic properties were changed by annealing or adjusting N2 partial pressure ratio. The film structures were investigated with X-ray diffraction and TEM, and the following results were obtained. (i) the as prepared films; amorphous like phase, (ii) the annealed films; homogeneous mixture of fine-grained α-Fe and (Ta, Nb, Zr) nitrides, (iii) the films annealed at higher temperatures; composite of grown grains of α-Fe and (Ta, Nb, Zr) nitrides. Among these films, the films (ii) exhibit good soft magnetic properties, small magnetostriction and high saturation magnetization up to 1.6 T. Furthermore, Fe-Ta-Zr-N alloy films show higher thermal stability of the soft magnetic properties.
40 citations
TL;DR: In this paper, the effects of stress on the flux distribution of non-oriented silicon steel due to shearing stress are examined and the deterioration of magnetization curve of nonoriented silicon steels is examined.
Abstract: Although the deteriorations of magnetic characteristics of silicon steel due to shearing stress have been observed, the degrees of the deteriorations have not been assessed quantitatively. As the technique of measuring microscopic distribution of flux density has recently been developed, the effects of stress on the flux distribution can be investigated quantitatively. The deteriorations of magnetization curve of non-oriented silicon steel due to shearing stress are examined.
36 citations
TL;DR: In this paper, the dependence of soft magnetic properties of α-Fe sputtered films of Fe-X-N (X=Zr, Hf, Nb, Ta) was investigated.
Abstract: To obtain ultra fine grains of α-Fe sputtered films of Fe-X-N (X=Zr, Hf, Nb, Ta), ternary systems in which each element X had strong affinity for nitrogen and ability of amorphous formation were prepared and the dependence of soft magnetic properties on composition of films was investigated. Good soft magnetic properties and high saturation flux density Bs were obtained in each system. In particular, Fe-Zr-N and Fe-Hf-N systems had a widespread soft magnetic region and exhibited zero magnetostriction and high Bs up to 16 kG at a certain composition.
34 citations
33 citations
TL;DR: In this article, the magnetic properties of Ni-Co-Fe thin films were examined as a function of deposition conditions and the anisotropic magnetoresistivity ratio of above 5% was obtained.
Abstract: Magnetoresistance effect and magnetic properties were examined for Ni-Co-Fe thin films as a function of deposition conditions. The anisotropic magnetoresistivity ratio of above 5% was obtained. ρav depends on the substrate temperature and film thickness, but Δρ does not depend. ρav and Δρ was measured as a function of temperature. Result show that the temperature dependence of ρav is quite similar to that of the MR ratio.
28 citations
TL;DR: In this article, an evaluation tool for the characterization of high-density recording thin film media is discussed based on the anomalous and the planar Hall effect, which is used to characterize ferromagnetic Co-Cr films and Co/Pd multilayers having perpendicular anisotropy.
Abstract: In this work an evaluation tool for the characterization of high-density recording thin film media is discussed. The measurement principles are based on the anomalous and the planar Hall effect. We used these Hall effects to characterize ferromagnetic Co-Cr films and Co/Pd multilayers having perpendicular anisotropy. The measurements set-up that was built has a sensitivity capable of measuring the hysteresis loops of 0.2x0.2 mm2 Hall structures in Co-Cr and jumps were observed in the Hall voltage as a function of the applied field. Easy-axis measurements have been carried out, but the results are not in complete agreement with conventional techniques. A thickness series of Co/Pd multilayers has been characterized with the planar Hall effect and the magnetoresistance ratio.
26 citations
TL;DR: The magnetic properties of silicon steel sheet under the condition of two-dimensional excitation (circular, elliptic and alternating with rotation of the direction) are investigated in this article.
Abstract: The magnetic properties of silicon steel sheet under the condition of two-dimensional excitation (circular, elliptic and alternating with rotation of the direction) are investigated. Two-dimensional magnetic measurement is a generic term introduced recently to comprise the measurement of magnetic properties of a specimen under the condition of rotating magnetic induction. Two-magnetic properties in silicon steel sheet are very sensitive to the axis ratio and the inclination angle of the magnetic flux density of longitudinal axis,because that is very effective to the anisotropy of the sheet.
24 citations
TL;DR: In this paper, the soft magnetic properties of Co-Fe alloy films are determined by the lattice strain rather than macroscopically induced uniaxial magnetic anisotropy Ku.
Abstract: Possibility for realization of soft magnetic properties was discussed for 40 wt%Co-Fe alloy films with large magnetostriction constants sputtered in Ar+N2 plasma. The value of Hc of about 10 Oe along the hard axis of magnetization was obtained after annealing at 500°C The soft magnetic properties for these films are mainly determined by the lattice strain rather than macroscopically induced uniaxial magnetic anisotropy Ku. The calculated magnetic anisotropy energy U in each grain, taking account of magnetoelastic energy, drastically increases with slight increases in the lattice strain. Therefore, in order to obtain excellent soft magnetic properties, the relaxation of lattice strain less than 0.1 % should be important.
21 citations
TL;DR: The magnetic behavior of co-evaporated Co-Cr is investigated in this paper, where the existence of highly pure Co regions has been proved by means of NMR analysis and the anisotropy of the film is discussed in relation to the texture and morphology of the films.
Abstract: The magnetic behaviour of co-evaporated Co-Cr is investigated. The existence of a process-induced compositional separation, generated by the special geometry of the opposing vapour beams, leads to enhanced perpendicular characteristics without the necessity of depositing the films at a raised substrate temperature. In this paper we present results of a thickness series ranging from 50 to 750 nm. The existence of highly pure Co regions has been proved by means of NMR analysis. The anisotropy of the film is discussed in relation to the texture and morphology of the films.
17 citations
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TL;DR: In this paper, the dependence of soft magnetic properties on the composition and annealing temperature was studied for sputtered (Fe1-XCoX)1-YNbY (0≤X≤1.2 in weight fraction) films.
Abstract: The dependence of soft magnetic properties on the composition and annealing temperature was studied for sputtered (Fe1-XCoX)1-YNbY (0≤X≤1.0, 0≤Y≤0.2 in weight fraction) films. The films with Y≥0.16 are amorphous while the films with 0≤X < 0.8, Y < 0.6 and 0.8≤X≤1.0, Y < 0.6 are of b.c.c. and f.c.c. structure, respectively. The lattice constant of the b.c.c. films increases with Nb content. The coercivity of the films annealed at 773 K for 3600 s exhibits a minimum of 400 A/m around Y=0.05 and X=0.3-0.8. The corresponding permeability and satuation magnetic flux density are 800 and 2 T, respectively. Coercivity depends much on the expansion of latticeconstant due to the addition of Nb and exhibits a minimum when the lattice constant of Fe-Co film is expanded 0.2%.
TL;DR: In this paper, the response of the readout signal employing both the thermal analysis and the scaler detection theory was calculated using both the same condition of the simulation, and a favorable agreement between the experimental results and the simulation results was obtained.
Abstract: MSR (Magnetically induced Super Resolution) by FAD (Front Aperture Detection) was demonstrated by the readout waveform of the isolated pit. We calculated the response of the readout signal employing both the thermal analysis and the scaler detection theory. As experiments carried out with the same condition of the simulation, we obtained a favorable agreement between the experimental results and the simulation results.
TL;DR: In this article, a new parameter ΔHc on M-H minor curves is introduced to estimate the standard deviation of the Hk distribution, which correlates strongly to coercivity squareness s* and half width of switching field distribution SFD.
Abstract: A new parameter ΔHc on M-H minor curves is introduced to estimate the standard deviation of the Hk distribution. The ΔHc correlates strongly to coercivity squareness s* and half-width of switching field distribution SFD. and needs no compensating for the demagnetizing field in perpendicular recording media. It was shown by computer simulation analysis that the magnetic recording performance depends greatly upon the particle's anisotropy field Hk distribution in recording media as well as coercivity and saturation magnetization. The narrow Hk distribution of Co-Cr sputtered media is derived from the high crystallinity, and leads to superior performance in high density recording.
TL;DR: The magnetic and magneto-optical properties of Co/Ru, Co/Au and Co/Pd multilayers were investigated in this paper, where the authors found that the surface anisotropy energies are almost equal.
Abstract: The magnetic and magneto-optical properties were investigated for Co/Ru, Co/Au and Co/Pd multilayers. Perpendicular magnetic anisotropy was found in the Co/Ru system. The anisotropy was enhanced by adopting a Pd base layer due to improvement of their periodicity and crystallinity. The Co/Ru multilayers with Co thicknesses less than 18A are easy to magnetize along the direction perpendicular to the film plane. As the Co thickness decreases, saturation magnetization per unit volume Co decreases in Co/Ru and Co/Au systems but increases in the Co/Pd system. The Co/Ru films exhibit small remanent magnetizations and coercive fields of a few hundred Oe. In spite of the difference of the nonmagnetic metal layer in the three systems, the surface anisotropy energies are almost equal. The difference of the volume anisotropy energy is due to demagnetization energy. The magneto-optical effect of Co/Ru multilayers diminishes in the short wave length region.
TL;DR: In this paper, single crystal Permalloy films were grown epitaxially on (001) GaAs substrates by sputtering method, and the relationship between crystal orientations for permalloys and GaAs were investigated.
Abstract: Single crystal Permalloy films were grown epitaxially on (001) GaAs substrates by sputtering method. The relationship between crystal orientations for Permalloy and GaAs are (001)NiFe//(001) GaAs, NiFe// GaAs. The crystal structures of Permalloy films are deformed from cubic to tetragonal. The films of positive and negative tetragonal strain have small and large unit cell volume, respectively. The films with small lattice constant in the film plane have large strain distribution. The magnetocrystalline anisotropy for the films of large strain distribution is small, and that for films of negative tetragonal strain is large.
TL;DR: In this paper, a two-dimensional lattice of magnetic dipoles is simulated on the Connection Machine and the results are used in the simulation of the thermomagnetic recording process, where a focused laser beam creates a hot spot and allows an external magnetic field to reverse the direction of local magnetization.
Abstract: Computer simulations of a two-dimensional lattice of magnetic dipoles are performed on the Connection Machine. The 256 x 256 hexagonal lattice is a discrete model for thin films of amorphous rare earth-transition metal (RE-TM) alloys, which have application as the storage media in erasable optical data storage systems. In these simulations the dipoles follow the dynamic equation of Landau-Lifshitz-Gilbert under the influence of an effective field arising from local anisotropy, near-neighbor exchange, classical dipole-dipole interactions, and an externally applied field. Using mean-field theory, we have calculated the temperature dependencies of the subnetwork magnetizations, the effective fields, the gyromagnetic coefficient, and the Gilbert damping parameter. These results are then used in the simulation of the thermomagnetic recording process, where a focused laser beam creates a hot spot and allows an external magnetic field to reverse the direction of local magnetization. The onset of nucleation and the dynamics of growth/contraction by domain wall motion have been studied by means of these simulations.
TL;DR: In this paper, a multitrack scanner for high density recording on conventional magnetic tape was developed, where the multiplexed recording device consists of a 2D array of gaps, while the magnetooptic readout system consisted of a Kerr transducer in contact with the tape, and of a CCD linear array for detection.
Abstract: New multitrack scanners have been developed for high density recording on conventional magnetic tape. The multiplexed recording device consists of a 2D array of gaps, while the magnetooptic readout system consists of a Kerr transducer in contact with the tape, and of a CCD linear array for detection.
TL;DR: In this paper, an analysis of the behavior of orthogonal-core type push-pull parametric transformers, taking the iron loss of the orthogon-cores and the copper loss of windings into consideration, is presented.
Abstract: This paper describes an analysis of the behavior of orthogonal-core type push-pull parametric transformers, taking the iron loss of the orthogonal-cores and the copper loss of the windings into consideration. The analysis was performed for the magnetic circuit of the orthogonal-core under magnetic saturation and with hysteresis. To improve the accuracy of calculations, the saturation characteristic was approximated by a series which includes terms of up to 21st order in the flux, and the hysteresis curve by a series including terms of up to 5th order in the exciting voltage. The calculated results show good agreement with experimental data. The analytical method presented here is useful for optimizing the design of push-pull parametric transformers.
TL;DR: In this paper, the initial permeability of Fe-Si polycrystalline thin films with (111) orientation parallel to the film plane was investigated and shown to have high permeability.
Abstract: Initial permeability of Fe-Si polycrystalline thin films was investigated. From calculation of magnetocrystalline anisotropy and initial permeability assuming that the magnetization is confined in a certain crystal plane, Fe-Si polycrystalline thin films with (111) orientation parallel to the film plane are expected to have high permeability of about 5000. Fe-6.9 wt%Si films were deposited on three kinds of underlayers with three different crystal orientations. Initial permeability of Fe-Si films on ZnSe underlayers with (111) orientation is about 1700, which is higher than that of the films with (100) or (110) orientation.
TL;DR: In this article, a relationship between transition lengths and head fields with media of various coercivities was described and the transition lengths were written by a single sided and a double sided MIG head on three thin film media which had the coercivity of 874, 1121 and 1270 Oe.
Abstract: This paper describes a relationship between transition lengths and head fields with media of various coercivities. The transition lengths were written by a single sided and a double sided MIG head on three thin film media which have the coercivity of 874, 1121 and 1270 Oe. The transition lengths were surveyed through the colloid SEM observation. The head fields of the MIG heads were analyzed by the finite-element method (FEM) with magnetic saturation taken into account. The following phenomena were found. First, the 2nd fields stray from saturated ferrite region near the interface between a metal film and ferrite core of the MIG head. Second, the transition lengths are spread by the influence of the 2nd field when the strength of the 2nd fild is higher than a half of the media coercivity. On the other hand, if the media coercivity is two-times higher than the 2nd field strength, the transition length is strongly related to the field gradient of the primary field at the recording zones.
TL;DR: In this paper, a planar-coil inductor with a closed magnetic circuit is proposed, and its characteristics are described, in order to prevent the occurrence of disconnections in the conductor.
Abstract: A break in the electrical or the magnetic path in a conductor or magnetic core is a serious problem for the fabrication of inductors. A planar-coil inductor with a closed magnetic circuit is proposed, and its characteristics are described. The conductor of the planar-coil inductor is patterned on a plane, in order to prevent the occurrence of disconnections in the conductor. To decrease the magnetic resistance, the cross-sections of core junctions, at which there is the risk of disconnection, are regulated. A trial-fabricated inductor consisted of one hundred magnetic cores, each of size 180 ?m × 180 ?m. The inductor dimensions were 2.3×2.3 mm2. The inductance of the device was 50 nH, and the resonance frequency was about 400 MHz.
TL;DR: In this article, amorphous Co-based films with dispersed fine nitrides were investigated and the properties of the obtained films were found to be related to the thickness of the film; as the thickness becomes less than 0.1 μm, the films become magnetically soft.
Abstract: In an effort to get an excellent magnetic thin film for micro inductance cores, amorphous Co-based films with dispersed fine nitrides were investigated. Amorphous structure, almost zero magnetostriction (λ) and high electrical resistivity were confirmed in the sputter deposited films. TEM observation clarified that these films were composed of two kinds of amorphous phases. Soft magnetic properties of the obtained films were found to be related to the thickness of the film; as the thickness becomes less than 0.1 μm, the films become magnetically soft. Based on this relation, we attempted to make multilayered films consisting of the Co-based thin layers and BN ceramics thin layers and obtained excellent properties with high ρ (>300μΩcm), lowλ (1×10-6 ) and high μ ( > 1000) at high frequency near 100 MHz.
TL;DR: In this article, the magnetic properties of Fe-Al-Si/Fe, FeAlSi/Ni-Fe, Al-Si and Ni-Fe multilayered films were investigated using RF sputtering equipment.
Abstract: Magnetic properties of Fe-Al-Si/Fe, Fe-Al-Si/Fe-Si and Fe-Al-Si/Ni-Fe multilayered films prepared by using RF sputtering equipment, were investigated. These multilayered films have initial permeability of more than 1000 without post-annealing; especially Fe-Al-Si/Fe and Fe-Al-Si/Fe-Si multilayered films have high saturation magnetic flux density Bs of more than 14 kG. For Fe-Al-Si/Ni-Fe multilayered film, magnetic properties are nearly constant and independent of the layer thickness. On the other hand, the thinner the thickness of each layer in Fe-Al-Si/Fe and Fe-Al-Si/Fe-Si multilayered films, the lower the coercivity is. In these films, the change in coercivity with the thickness of each layer seems to be affected by lattice distortion and crystal structure rather than crystallite size.
TL;DR: In this paper, the relationship between the formation of iron nitride films and plasma parameters (space potential Vs, electron density Ne and electron temperature Te) was investigated on plasma reactive evaporation.
Abstract: The relationship between the formation of iron nitride films and plasma parameters (space potential Vs, electron density Ne and electron temperature Te) were investigated on plasma reactive evaporation. Vs, Ne and Te of the reactive nitrogen plasma were determined by the single probe method. The formation of the nitrides was found to depend strongly on Vs and Ne, respectively. The nitrogen concentration increased with increases in Ne and Vs. Especially α'phase was obtained on the condition of Ne=1∼3×109cm−3 and Vs=50 V or 300∼500 V. The nitride process in the plasma reactive evaporation was also investigated by using the evaporated iron films exposed to nitrogen plasma. The nitrides were found to be mainly formed on the surface of the films.
TL;DR: In this paper, a fast algorithm for reconstructing stray magnetic fields of a magnetic head by electron beam tomography and its application are presented. But this algorithm requires the magnetic field distribution on a measurement plane just beyond the gap.
Abstract: A new fast algorithm for reconstructing stray magnetic fields of a magnetic head by electron beam tomography and its application are presented. We have already proposed the 3-D reconstruction method of stray magnetic fields using ART method for electron beam tomography. In this new algorithm, magnetic field distribution on a measurement plane just beyond the gap is first reconstructed using ART method. Then the entire magnetic field distribution is calculated numerically by boundary element method using the reconstructed magnetic field on the measurement plane as a boundary condition. Using this method, total reconstruction time is shortened and reconstruction accuracy is quite improved. An example of reconstruction of magnetic field of an MIG head is described. From these results and also analytical results by 2-D finite element method, it is shown that the new algorithm is useful in reconstructing the entire magnetic field distribution rather accurately.