Accession Number : AD0616038

Title :   MAGNETORESISTANCE BELOW MAGNETIZATION SATURATION IN PLASTICALLY DEFORMED NICKEL DOWN TO LIQUID HELIUM TEMPERATURES,

Corporate Author : TECHNION - ISRAEL INST OF TECH HAIFA

Personal Author(s) : Hirsch,A. A.

Report Date : 24 FEB 1964

Pagination or Media Count : 12

Abstract : A phenomenological analysis is outlined for the magnetoresistance effect in plastically deformed pure nickel below magnetization saturation down to liquid helium temperatures, which is based on the assumption of time dependent hysteresis phenomena. Both preferred orientation and induced uniaxial magnetic anisotropy are expected to be created by the plastic flow, when the deformation of the polycrystalline material is carried out by cold rolling with high reduction in the thickness of the sample. The magnetoresistance hysteresis loops can be ascribed to a magnetization process, which can be discussed from the viewpoint of a domain structure, in which a rotational process of reorientation of spins predominates. The field interval corresponding to nonsaturated states of magnetization is higher than expected in ordinary bulk material, where no orientation and size effects are of importance for the magnetization reversal. The dynamic magnetoresistance loops performed at constant drive amplitude of the applied magnetic field, when a triangular waveform and low frequencies are used, are different from the static loops which can be described when taking into consideration the tensor of the electrical resistivity in a cubic ferromagnetic crystal. These deviations become appreciable at liquid helium temperatures, and as suggested in this analysis, they may be related to a mechanism of magnetization reversal having a relatively long switching time. (Author)

Descriptors :   (*NICKEL, MAGNETIC PROPERTIES), (*ELECTRICAL RESISTANCE, NICKEL), (*MAGNETIC PROPERTIES, CRYOGENICS), DEFORMATION, HYSTERESIS, TENSOR ANALYSIS, MAGNETIC FIELDS, ANISOTROPY

Distribution Statement : APPROVED FOR PUBLIC RELEASE