Showing papers on "Colossal magnetoresistance published in 1990"

The paramagnetic-ferromagnetic transition in reentrant spin-glasses-a magnetoresistance study in ultra-low magnetic fields

Abstract: The longitudinal magnetoresistance has been measured in the spin-glass and reentrant spin-glass states of Au-14 at.%Fe and amorphous (Fe1-xNix)77Si10B13 alloys by a new technique which involves applied fields of less than two gauss. The measurements have concentrated on the paramagnetic-ferromagnetic transition where in both crystalline and amorphous systems a curious negative magnetoresistance has been found over a small temperature range, which rapidly changes sign as the ferromagnetic state becomes established with decrease of temperature. From measurements of the field dependence of the magnetoresistance near the Curie temperature, the negative contribution, as well as the positive contribution, is found to continue to develop into the ferromagnetic state. The model used by Beck (1985), modified with the addition of a pin-glass type background matrix, is proposed from the study for the ferromagnetic state of these alloys.

Anomalous Magnetoresistance in LaB6 Thin Films

Abstract: Thin films of LaB 6 were prepared on sapphire, Si and GaAs by electron-beam deposition. Superconductivity was not observed above 1.6 K, and the anomalous magnetoresistance, associated with the weak localization effects, indicated that the spin-orbit scattering rather than the magnetic impurity scattering is strong in this film. From the detailed analysis of the magnetoresistance, we estimated the superconducting transition temperature of our sample is, if it exists, less than 40 mK. It turned out that the parallel magnetoresistance is larger in magnitude than the perpendicular one. This large parallel magnetoresistance is beyond the localization theory, and has never been observed in other materials.

Anisotropic magnetoresistance of GdBa2Cu3Oy film

Abstract: The anisotropy of transverse magnetoresistance has been measured below the gadolinium Neel temperature in evaporated single crystal films of GdBa 2 Cu 3 O y ( y c -axis On the other hand, with the field perpendicular to the c -axis, the magnetoresistance shows a single peak This behavior of the magnetoresistance should be related to the magnetism of Gd ions Evidence of the interaction between Gd ions and the Cu(2) planes is expected

Anisotropic Magnetoresistance of Amorphous Fe–Zr Alloy Films

Abstract: Anisotropic magnetoresistance and related properties were measured for amorphous Fe100-xZrx (x=10, 14) films at temperatures between 20 K and the Curie point. The anisotropic magnetoresistance was found to be 0.4–0.5% at 20 K, decreasing with increasing temperature roughly in proportion to the third power of the magnetization. This agrees with the power law derived from the molecular field approximation.