Peculiarities of the electronic transport in half-metallic Co-based Heusler alloys

[摘要] Electrical, magnetic and galvanomagnetic properties of half-metallic Heusler alloys of Co(2)YZ (Y = Ti, V, Cr, Mn, Fe, Ni, and Z = Al, Si, Ga, Ge, In, Sn, Sb) were studied in the temperature range 4.2-900 K and in magnetic fields of up to 100 kOe. It was found that varying Y in Co2YZ alloys affects strongly the electric resistivity and its temperature dependence q(T), while this effect is not observed upon changing Z. When Y is varied, extrema (maximum or minimum) are observed in q(T) near the Curie temperature TC. At T < TC, the q(T) behavior can be ascribed to a change in electronic energy spectrum near the Fermi level. The coefficients of normal and anomalous Hall effect were determined. It was shown that the latter coefficient, RS, is related to the residual resistivity rho(0) by a power law RS similar to rho(0) k/MS with MS the spontaneous magnetization. The exponent k was found to be 1.8 for Co(2)FeZ alloys, which is typical for asymmetric scattering mechanisms, and 2.9 for Co2YAl alloys, which indicates an additional contribution to the anomalous Hall effect. The temperature dependence of resistivity at low temperatures is analyzed and discussed in the frame of the two-magnon scattering theory. (C) 2017 Elsevier B.V. All rights reserved.

[发布日期] 2018-08-01

[效力级别]  Proceedings Paper

[关键词] Heusler alloys;Half metallic ferromagnets;Resistivity;Hall effect