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

Abstract

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 affects strongly the electric resistivity and its temperature dependence $\rho (T)$, while this effect is not observed upon changing Z. When Y is varied, extrema (maximum or minimum) are observed in $\rho (T)$ near the Curie temperature $T_C$. At $T<T_C$, the $\rho (T)$ behavior can be ascribed to a change in electronic energy spectrum near the Fermi level. The coefficients of the normal and anomalous Hall effect were determined. It was shown that the latter coefficient, $R_S$, is related to the residual resistivity ${\rho }_0$ by a power law $R_S\sim {\rho }_0^k/M_S$ with $M_S$ 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 Co${}_2$YAl 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 framework of the two-magnon scattering theory.

Invited Report on the Moscow International Symposium on Magnetism MISM-2017, pdf only, 6 pages, J. Magn. Magn. Mater., in press

References in corpus (3)

• Half-metallic ferromagnets: From band structure to many-body effects
• Calculated electronic and magnetic properties of the half-metallic, transition metal based Heusler compounds
• Half-Metallic Ferromagnetism in the Heusler Compound Co${}_2$FeSi revealed by Resistivity, Magnetoresistance, and Anomalous Hall Effect measurements

Cited by in corpus (7)

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• Half-Metallic Ferromagnets and Spin Gapless Semiconductors
• Unusual kinetic properties of usual Heusler alloys
• Electronic, magnetic and galvanomagnetic properties of Co-based Heusler alloys: possible states of a half-metallic ferromagnet and spin gapless semiconductor
• Peculiarities of electronic transport and magnetic state in half-metallic ferromagnetic and spin gapless semiconducting Heusler alloys
• Co${}_2$MnZ (Z = Al, Si, Ga, Ge, Sn) Heusler alloys as candidate materials for spintronic and microelectronic applications: Electronic structure, transport, and magnetism