• Cohen, L. F.
• Androulakis, J.
• Branford, W. R.
• Miyoshi, Y.
• Bugoslavsky, Y.
• Clowes, Steven
• Gardelis, S.
• Migiakis, P.
• Giapintzakis, J.

Abstract

Several polycrystalline samples of the half-Heusler alloy NiMnSb were grown by arc melting of stoichiometric and nonstoichiometric amounts of high-purity constituent elements. The structure and the phase-purity of the prepared samples were examined systematically by powder x-ray diffraction. The transport properties of the best sample, with saturation magnetization M<SUB>s</SUB>(5 K)=4<SUB>μB</SUB>/formula unit, were studied by measuring electrical resistivity, thermal conductivity, and thermopower. Features in both magnetic and transport data are consistent with NiMnSb being in a half-metallic state at low temperatures, i.e., the conduction electrons are fully spin polarized. However, point-contact Andreev reflection measurements on the same sample at 4.2 K demonstrate only ∼45% spin polarization....

Topics

• resistivity
• phase
• powder X-ray diffraction
• thermal conductivity
• magnetization
• saturation magnetization
• spin polarization