The finite-temperature densities of states for half-metallic ferromagnets
Department of Physics and Astronomy and Center for Materials
Research and Analysis, University of Nebraska Lincoln - Lincoln,
NE 68588, USA
Accepted: 27 February 2002
A unitary spinor transformation is used to show that the spin-down density of states (DOS) of half-metallic ferromagnets becomes nonzero at finite temperatures. In a strict sense, this thermally activated spin mixing means that half-metallic ferromagnetism is limited to zero temperature. Similar effects are created by crystal imperfections, interfaces, and surfaces. The calculations, which imply that the finite-temperature resistivity of an individual spin channel is never infinite, are used to discuss recent experimental work on half-metallic oxides and Heusler-type alloys.
PACS: 71.20.Lp – Intermetallic compounds / 73.20.At – Surface states, band structure, electron density of states / 75.25.+z – Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source X-ray scattering, etc.)
© EDP Sciences, 2002