Structural and magnetic properties of NiMnSb/InGaAs/InP(001)

Journal Article · Fri Apr 01 04:00:00 EST 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1873036· OSTI ID:20668283

Koveshnikov, A; Woltersdorf, G; Liu, J Q; Kardasz, B; Mosendz, O; Heinrich, B; Kavanagh, K L; Bach, P; Bader, A S; Schumacher, C; Ruester, C; Gould, C; Schmidt, G; Molenkamp, L W; Kumpf, C ^[1]

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1. Department of Physics, Simon Fraser University, Burnaby, BC V5A 1S6 (Canada)

The structural and magnetic properties of NiMnSb films, 5-120 nm thick, grown on InGaAs/InP(001) substrates by molecular-beam epitaxy, were studied by x-ray diffraction, transmission electron microscopy (TEM), and ferromagnetic resonance (FMR) techniques. X-ray diffraction and TEM studies show that the NiMnSb films had the expected half-Heusler structure, and films up to 120 nm were pseudomorphically strained at the interface, greater than the critical thickness for this system, about 70 nm (0.6% mismatch to InP). No interfacial misfit dislocations were detected up to 85 nm, however, relaxation in the surface regions of films thicker than 40 nm was evident in x-ray reciprocal space maps. TEM investigations show that bulk, planar defects are present beginning in the thinnest film (10 nm). Their density remains constant but they gradually increase in size with increasing film thickness. By 40 nm these defects have overlapped to form a quasicontinuous network aligned closely with <100> in-plane directions. The associated strain fields and or compositional ordering from these defects introduced a reduction in crystal symmetry that influenced the magnetic properties. The in-plane and perpendicular FMR anisotropies are not well described by bulk and interface contributions. In thick films, the in-plane uniaxial and fourfold anisotropies increased with increasing film thickness. The lattice defects resulted in a large extrinsic magnetic damping caused by two-magnon scattering, an increase in the coersive field with increasing film thickness, and a lower magnetic moment (3.6 Bohr magnetons) compared to the expected value for the bulk crystals (4 Bohr magnetons)

• OSTI ID: 20668283
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
ANTIMONY ALLOYS
COERCIVE FORCE
CRYSTAL GROWTH
DISLOCATIONS
FERROMAGNETIC RESONANCE
GALLIUM ARSENIDES
INDIUM ARSENIDES
INDIUM PHOSPHIDES
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MANGANESE ALLOYS
MOLECULAR BEAM EPITAXY
NICKEL ALLOYS
STRESS RELAXATION
SUBSTRATES
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION