Minority-spin band parameters in a NiMnSb thin film determined by spectral conductivity

Journal Article · Wed Dec 01 04:00:00 EST 2004 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1811779· OSTI ID:20658100

Grigorescu, C E.A.; Trodahl, H J; Strickland, N M; Bittar, A; Manea, S A; Giapintzakis, J; Monnereau, O; Notonier, R; Kennedy, V J ^[1]

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1. National Institute R and D Optoelectronics INOE, 2000-Bucharest (Romania)

NiMnSb is expected to be a ferromagnetic half metal, an expectation that is based in part on band structure calculations. Here we report optical conductivity studies of the band structure for a film prepared by pulsed laser deposition onto a Si substrate held at a relatively low temperature as is required for some device applications--films which are susceptible to site disorder associated with the vacant site in this half-Heusler compound. We demonstrate that the direct interband transitions are essentially unshifted in comparison with bulk material, though they are somewhat broadened. Below the direct-transition absorption edge we report the presence of indirect spin-reversing transitions between the Fermi energy (E{sub f}) and the extrema of the minority-spin valence and conduction bands, providing a measure of the band edge energies. Both of these edges appear closer to E{sub f} than is seen in well-ordered bulk NiMnSb, with the conduction-band minimum showing weight at only 200 cm{sup -1} above E{sub f}, close enough to have substantial occupation at ambient temperature.

• OSTI ID: 20658100
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 96; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
AMBIENT TEMPERATURE
ANTIMONY ALLOYS
ENERGY BEAM DEPOSITION
FERMI LEVEL
FERROMAGNETIC MATERIALS
LASER RADIATION
MANGANESE ALLOYS
MORPHOLOGY
NICKEL ALLOYS
PULSED IRRADIATION
SILICON
SPIN
SUBSTRATES
TERNARY ALLOY SYSTEMS
THIN FILMS
VALENCE