S. Ishio

Large magnetoresistance effect in 82Ni-Fe/Al-Al2O3/Co magnetic tunneling junction

Abstract A large magnetoresistance ratio ( ΔR / R = 2.7% at room temperature and 3.5% at 77 K) was observed for the first time in 82Ni-Fe/Al-Al 2 O 3 /Co junction.

Giant magnetoresistance and interlayer exchange coupling in Ni-Co/Cu multilayer films

Abstract The oscillation of giant magnetoresistance and interlayer exchange coupling as a function of Cu thickness was studied for Ni-Co/Cu multilayer films prepared by magnetron sputtering onto a glass substrate. They had a fcc (111) preferred orientation parallel to the growth direction. Both the value of magnetoresistance ratio and interlayer exchange coupling strength increased with increasing Co content, which were in qualitative agreement with theoretical calculations. The strength of exchange coupling was proportional to the square of the saturation magnetization.

Dependence of magnetoresistance on temperature and applied voltage in a 82Ni-Fe/Al-Al2O3/Co tunneling junction

Abstract The dependence of magnetoresistance on temperature T and on the applied voltage V in a 82Ni-Fe/Al-Al 2 O 3 /Co tunneling junction has been studied. The magnetoresistance Δ R / R increased rapidly at T ⩽ 30 K and V ⩽2.5 mV. The result is discussed by taking into account the tunneling conductance due to ferromagnetic tunneling and nonferromagnetic tunneling causing the zero-bias anomaly.

Magnetic properties and exchange interactions in (GdxFe1-x)80Si12B8 amorphous alloys

Abstract Magnetization Curie temperature and magnetovolume effects of amorphous (Gd x Fe 1- x ) 80 Si 12 B 8 alloys (0.1 ⩽ x ⩽ 1.0) were investigated. Gd 80 Si 12 B 8 is an asperomagnet having the Curie temperature of 129 K. The large susceptibility of the asperomagnet enhances the forced volume magnetostriction for x more than 0.7, which reaches about 100 × 10 -10 Oe -1 at x = 1.0 and T = 30 K. The Mossbauer study revealed a decrease of the Fe magnetic moment with an increase of Gd content. Exchange interactions J FeFe and J FeGd evaluated by the fitting of σ - T curves are discussed and compared with those of crystalline GdFe compounds.

Oblique incidence effects in evaporated iron thin films

Abstract Magnetic properties, electrical resistance and microstructures of evaporated iron thin films deposited at an oblique angle of incidence have been investigated. The structure differs along the thickness direction and contains interstices. It is observed by the dark field image that the columns formed appear to be single-crystals at high incidence angles.

Composition dependence of giant magnetoresistance in NixCo1-x/Cu (x = 0−1) multilayer films

Abstract Ni x Co 1- x /Cu multilayers were prepared onto a glass substrate by sputtering. Both oscillations of magnetoresistance ratio and interlayer exchange coupling strength as a function of the Cu layer thickness were observed. The magnitude of MR ratio and the interlayer exchange coupling strength increased with increasing Co content. Cu layer thickness for the MR peaks increased also with increasing Co content.

Zero magnetostriction composition in Fe-Ni-Co ternary alloy system

Abstract Two contour lines with zero saturation magnetostriction were found in Fe-Ni-Co ternary alloy system.

Magnetoresistance in Ni-Fe/Cu multilayers formed by sputtering

Abstract The dependence of magnetoresistance on the thickness of Cu layer, the thickness of magnetic layer, the thickness of buffer layer, the number of layered stack and the composition of magnetic layer has been investigated for the Ni x Fe 100- x /Cu multilayers.

Temperature dependence of forced volume magnetostriction in fcc Fe-Ni alloys

Abstract The forced volume magnetostriction of the fcc Fe-Ni Invar alloys has been measured in the temperature range from 77 to 900 K to elucidate the magnetovolume effect at finite temperatures. The temperature dependence of (θ ω/θ( H/M ) is evaluated as well as (θ ω/θ H ), where ω is the volume expansion. These results are discussed using a phenomenological model for the magnetovolume effect which takes into account the contribution of the correlation between local magnetic moments.

On the invar effect of Fe-based amorphous alloys

Abstract Spontaneous volume magnetostriction and forced volume magnetostriction of various Fe-based amorphous alloys have been studied. Invar characteristics of amorphous alloys depend on the electron number per transition metal atom, irrespective of the kinds of transition metal and metalloid elements.