An adaptive algorithm for n-body field expansions
Weinberg, Martin D.
1998-05-28
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Comment: 4 pages, 1 fig. Paper submitted to the 8th MMM-Intermag conference.
Typos corrected
We carried out Point Contact Andreev Reflection (PCAR) spin spectroscopy
measurements on epitaxially-grown ferromagnetic In1-xMnxSb epilayers with a
Curie temperature of ~9K. The spin sensitivity of PCAR in this material was
demonstrated by parallel control studies on its non-magnetic analog,
In1-yBeySb. We found the conductance curves of the Sn point contacts with
In1-yBeySb to be fairly conventional, with the possible presence of
proximity-induced superconductivity effects at the lowest temperatures. The
experimental Z-values of interfacial scattering agreed well with the estimates
based on the Fermi velocity mismatch between the semiconductor and the
superconductor. These measurements provided control data for subsequent PCAR
measurements on ferromagnetic In1-xMnxSb, which indicated spin polarization in
In1-xMnxSb to be 52 +- 3%.
We report on the study of the structural, magnetic, and transport properties of highly textured MnBi films with the Curie temperature of 628 K. In addition to detailed measurements of resistivity and magnetization, we measure transport spin polarization of MnBi by Andreev reflection spectroscopy and perform fully relativistic band-structure calculations of MnBi. A spin polarization from 51% ± 1% to 63% ± 1% is observed, consistent with the calculations and with an observation of a large magnetoresistance in MnBi contacts. The band-structure calculations indicate that in spite of almost identical densities of states at the Fermi energy, the large disparity in the Fermi velocities leads to high transport spin polarization of MnBi. The correlation between the values of magnetization and spin polarization is discussed.
We report on the study of the structural, magnetic and transport properties
of highly textured MnBi films with the Curie temperature of 628K. In addition
to detailed measurements of resistivity and magnetization, we measure transport
spin polarization of MnBi by Andreev reflection spectroscopy and perform fully
relativistic band structure calculations of MnBi. A spin polarization from
51\pm1 to 63\pm1% is observed, consistent with the calculations and with an
observation of a large magnetoresistance in MnBi contacts. The band structure
calculations indicate that, in spite of almost identical densities of states at
the Fermi energy, the large disparity in the Fermi velocities leads to high
transport spin polarization of MnBi. The correlation between the values of
magnetization and spin polarization is discussed.
Comment: 6 pages, revtex, epsfigs embedded (two color figs)
