We report on the magnetotransport properties of epitaxial thin films of In 1−x Mn x Sb dilute magnetic semiconductor grown by metal-organic vapor-phase epitaxy. At temperatures below 10 K, a negative magnetoresistance dominates the magnetotransport that is attributed to spin-dependent scattering by localized magnetic moments. Above 10 K, the magnetoresistance is positive and is well described by a two-band model consisting of spin-split hybridized p-d subbands with different conductivities. Hall effect measurements show an anomalous behavior that persists up to room temperature, providing an indication of ferromagnetic order. In addition, magnetization measurements reveal distinct hysteresis loops at room temperature which confirms the ferromagnetism of the films.

We report ferromagnetism in single phase, epitaxial In 1−x Mn x Sb alloy films, with x Յ 0.035, grown by metalorganic vapor phase epitaxy. The alloy films exhibit well-defined magnetization versus magnetic field hysteresis loops from 4-298 K. High-field magnetotransport measurements indicated that the Hall resistivity has a nonlinear dependence on magnetic field. Ferromagnetism is supported by observation of an anomalous Hall effect and clear hysteresis in the anomalous Hall resistivity versus magnetic field measurements. Zero field cooled and field cooled magnetization measurements show reversibility indicating absence of second phase precipitates. The temperature dependence of the magnetization is described by a modified Brillouin function with a T C of 590 K. The observed magnetic and magnetotransport properties are attributed to carrier mediated ferromagnetism involving Mn and its complexes that form shallow or resonant electronic states through correlated substitution in the semiconductor host.

The magnetic and electronic structure of Mn in In0.965Mn0.035Sb ferromagnetic semiconductor thin film was studied by x-ray absorption spectroscopy and x-ray magnetic circular dichroism. Comparison with atomic multiplet calculations suggests that manganese substitutes on sites with tetrahedral symmetry. Strong magnetic dichroism was observed from 5 to 300 K, at an applied field of 2 T. The temperature dependence of dichroism indicates presence of two magnetic Mn species having very similar spectral features. A high temperature species dominates the dichroic response over 50–300 K and a low temperature species is observed below 50 K.

We present an atomically resolved study of metal-organic vapor epitaxy grown Mn doped InSb that is ferromagnetic at room-temperature. Both topographic and spectroscopic measurements have been performed by cross-sectional scanning tunneling microscopy. The measurements show a perfect crystal structure without any precipitates and reveal that Mn acts as a shallow acceptor. The Mn concentration obtained from the cross-sectional STM data compares well with the intended doping concentration. No second phase material or (nano)clustering of the Mn was observed. While the pair correlation function of the Mn atoms showed that their local distribution is uncorrelated beyond the STM resolution for observing individual dopants, disorder in the Mn ion location is clearly noted. We discuss the implications of the observed disorder for a number of suggested explanations of the room-temperature ferromagnetism in Mn doped InSb grown by metal-organic vapor epitaxy.

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