A. Yamada

Magnetism and magnetoresistance of Co/Cu multilayer films produced by pulse control electrodeposition method

We have attempted to produce electrodeposited multilayer films (Co/Cu) by using the pulse generator circuit controlled by the microcomputer, and have investigated the magnetic properties, magnetoresistance and crystal state in these films. The magnetoresistance is dependent on both the thickness of ferromagnetic and non-magnetic layers. The adequate thickness of Co ferromagnetic layer and Cu non-magnetic layer is required to make the large magnetoresistance ratio. Antiparallel alignment of magnetic spin is a necessary but not sufficient condition in order to generate the GMR of multilayer films.

Electrical resistivity and magnetism of Fe/Si multilayers prepared by oblique incidence evaporation

We discussed the origin of the uniaxial magnetic anisotropy of the Fe/Si multilayered films prepared by varying oblique evaporation angle from the view of electric resistance. The tendency in the incidence angle dependence of the uniaxial magnetic anisotropy is in agreement with that of the angle dependence of the electric resistance ratio. The origin of the magnetic anisotropy seems to be due to anisotropic arrangement of atoms in the film.

Magnetic properties and magnetoresistance of Fe/Cr multilayer films prepared by vapor deposition and electrodeposition

Abstract Fe/Cr system multilayers were prepared by electron beam deposition and electrodeposition. The effect of Cr alloying of the Fe layers, Fe alloying of the Cr layers and annealing on the magnetic properties and the magnetoresistance (MR) have been investigated. MR depends on the alloy composition in the Fe-rich ferromagnetic layer and the Cr-rich nonmagnetic layer. The MR ratio decreases remarkably with increasing content of Fe into the Cr interlayer. However, MR was not observed for the electrodeposited films.

Electric resistivity and magnetoanisotropy in Fe/Si evaporated multilayers

Uniaxial magnetic anisotropy of the films can be induced in ferromagnetic thin films evaporated at oblique incidence even in absence of a magnetic field. The induced uniaxial magnetic anisotropy was remarkable in multilayered films formed varying the oblique incidence angle, and the easy axis of the anisotropy is along the perpendicular direction of the incidence of evaporation. In this paper, we have discussed the origin of the uniaxial magnetic anisotropy of Fe/Si multilayered films, prepared by varying the oblique evaporation angle, from the viewpoint of electric resistance. The tendency in the incidence angle dependence of uniaxial magnetic anisotropy is in agreement with that of the angle dependence of the electric resistance ratio. The origin of the uniaxial magnetic anisotropy of thin films induced by oblique angle deposition is due to anisotropic arrangement of atoms in the films.

Magnetization and Magnetoresistance of Fe 3 O 4 Prepared by Ball Milling Method

Recently, magnetoresistance eŠects have been found in the metal oxides produced by variety of methods. We have investigated the magnetoresistance(MR) eŠect of magnetite(Fe3O4) produced by Ball Milling. MR ratio was increased from 1.4 to 2.2 after ball milling for 10 hours. After annealing at 623 K for 1 hour, MR ratio increased to 3.3. It seems that the origin of the magnetoresistance eŠects for the magnetite Fe3O4 is related to the precipitation of Fe2O3. MR ratio increased monotonically with decreasing of temperature, and showed 4 at the temperature of 100 K.