Noboru Tsuya

Magnetomechanical coupling and variable delay characteristics by means of a giant ΔE effect in iron‐rich amorphous ribbon

The saturation magnetostriction constants λs of amorphous (Fe0.9Co0.1)xSiyBz and (Fe1−xCox)78Si8B14 ribbons were measured at room temperature by a three terminal capacitance method, and the largest constant λs was found to be 44×10−6 for the composition (Fe0.9Co0.1)0.83B0.14. The magnetomechanical coupling factor k and the giant ΔE effect of the amorphous Fe78Si10B12 ribbons were also observed. These values depended on the annealing of the ribbons in a magnetic field, and were larger than those previously reported. The largest coupling factor was found to be 0.75 for the ribbon annealed at 410 °C for 12 minutes and the largest ΔE effect to be 1.9 for a ribbon annealed at 410 °C for 10 minutes. The variable delay time, by using Fe78Si10B12 ribbons with 20, 15 and 5 μm thick was also measured from 150 kHz to 10 MHz as a function of the frequency.

Giant ΔE effect and magnetomechanical coupling factor in amorphous Fe 80 P 13 C 7 ribbons

The magnetomechanical coupling factor k, the Youngs modulus E and the \DeltaE effect as a function of bias field were measured by a mechanical resonance method of amorphous Fe 80 P 13 C 7 ribbons which were annealed at different temperatures in a magnetic field. In the ribbon which was annealed at 350°C for 20 minutes, a remarkably large coupling factor k was found in the bias field 5 Oe to be 0.53, which was almost the same as the value of the high magnetostrictive rare earth-Fe 2 . The \DeltaE effect increased with the increase of the bias field, took a gigantic value 0.8 at about 5 Oe and then decreased monotonically with the increase of the bias field. The \DeltaE effect is known to correspond to a change in sound velocity, so that the change of the sound velocity was also observed as a function of the frequency from 100kHz to 1MHz in a delay line using the ribbons.

Saturation magnetostriction and volume magnetostriction of Fe-Ni-Co amorphous ribbons

The saturation magnetostriction and the volume magnetostriction in amorphous ribbons of Fe-Ni-Co system were measured from 77K to room temperature, by a three terminal capacitance method. The ternary diagram were given of the saturation magnetostriction and volume magnetostriction in (Fe x Co y Ni 1-x-y ) 78 Si 8 B 14 system. It was found that the largest saturation magnetostriction constant is 36×10-6for the composition Fe 65 Co 13 Si 8 B 14 at room temperature. The temperature dependence of the saturation magnetostriction and the volume magnetostriction in Fe-Ni-Co system were not a simple function of the temperature. The maximum value of volume magnetostriction δω/δH was observed for Fe 78 Si 8 B 14 to be 24×10-10Oe-1at room temperature.

Magnetostriction Measurement by Three Terminal Capacitance Method

The saturation magnetostriction constants λ100 and λ111 of YIG and Fe(1-x)Alx (x=0.17, 0.20, 0.23, 0.25) single crystals were measured by a capacitance method at room temperature. The capacitance cell used in this experiment was designed to be convenient for measuring the constants of spherical samples from 0.5 mm to 10 mm in diameter with sufficient sensitivity to measure elongations of 0.1A. The magnetostriction constants λ100 and λ111 of YIG were -1.43×10-6 and -2.88×10-6 respectively and were in very good agreement with the values observed by Callen, Clark, DeSavage, Coleman and Callen.

Ribbon-form silicon-iron alloy containing around 6% silicon

By a roller quenching method, XSi-(100-X)Fe ribbons ( 6.0 \leq X \leq 7.0 ) in the crystalline state were prepared. The size of them was 20 to 150μm in thickness, 2 to 25 mm in width and 5 to 10 m in length, and after annealing all of them were mechanically very soft so as to be bent 180°. In the grain structure of the as-prepared ribbons the columnar grains about 10μm in diameter were observed to grow from the surface to the middle part of the ribbon thickness. The texture of them have

On the Ferrimagnetism of Iron Selenides

The thermomagnetic properties of iron selenides FeSe x with various selenium contents x were measured as functions of temperature. The thermomagnetic curves obtained belong to the ordinary Weiss type. It was also found that the magnetization at the boiling temperature of liquid nitrogen increases with the selenium content, reaches its maximum value. 35 gauss, at x =1.23, and then decreases again with further increase of x . The Neel temperature was approximately 150°C in the range of x from 1 to 1.26 whereas it decreases gradually with further increase of x and approaches to its lowest value 30°C at x =1.35. The origin of the magnetization of this substance was discussed based on the theory of ferrimagnetism.

Crystallization Process from Amorphous PbTiO3

Investigation has been made of the crystallization from the rapidly quenched amorphous state of PbTiO3 utilizing DTA and Raman spectroscopy. The DTA curves reveal sharp exothermic peaks between 500 and 600°C on heating the as-quenched samples. Essential differences between the Raman spectra from the as-quenched state and those from the crystalline state have been recognized: the soft mode observed in the crystalline state is found not to exist in the as-quenched state. By annealing samples, a dramatic change in the Raman spectra due to the structural relaxation is clearly visible.

On the Magnetic Properties of the System MnSb-CrSb

The change of magnetic properties due to the replacement of manganese by chromium in manganese antimonide (MnSb), which is of the NiAs structure, was investigated. It was found that, with the increase of the concentration of chromium, the magnetic behaviour of these compounds (Mn 1- x Cr x )Sb changes as follows: (1) at x =0 (MnSb), the temperature-magnetization curve shows typical behaviour of ferromagnetic substance, (2) in the range 0.1≤ x ≤0.7, it deviates remarkably from the Weiss curve in proportion with the chromium content, and the temperature dependence of the reciprocal susceptibility above the Curie point is of a ferrimagnetic type. (3) In the range 0.8≤ x ≤0.9 a transition from ferrimagnetic to antiferromagnetic was observed, and finally (4) at x =1 (CrSb) a typical antiferromagnetism could be seen. A short discussion of such transitions is given.

Amorphous Ribbons of LiNbO3, PbTiO3 and (PbTiO3)0.9(B2O3)0.1

Amorphous ribbons of LiNbO3, PbTiO3, and (PbTiO3)0.9(B2O3)0.1 were obtained by a roller quenching technique. These ribbons were examined by electron diffraction as well as by X-ray diffraction experiments, and were proved to be in the amorphous state. Their dielectric constant increased rapidly with increase of temperature.

Annealing of silicon-iron ribbons containing around 6.5 wt% silicon

The magnetic properties and the grain structure of 6.6Si.93.4Fe ribbons made by a rapid quenching roll method were measured after annealing the ribbons at about 1180°C for 60 minutes under pressures ranging from 5×10-1to 1.5×10-3Torr. By annealing the ribbon under the pressure of 3 × 10-1Torr the ribbon had highly oriented