Unconventional ferromagnetism and transport properties of (In,Mn)Sb dilute magnetic semiconductor

TL;DR

This study investigates the magnetic and transport properties of (In,Mn)Sb semiconductors, revealing room-temperature ferromagnetism, unconventional magnetization behavior, and high spin polarization, advancing understanding of carrier-mediated ferromagnetism in dilute magnetic semiconductors.

Contribution

It reports the first observation of room-temperature ferromagnetism and unconventional magnetization behavior in (In,Mn)Sb, and explores the correlation between magnetic states and transport properties using contact spectroscopy.

Findings

Ferromagnetic response detected up to room temperature.

Unconventional reentrant magnetization behavior observed.

High spin polarization of charge carriers (up to 65%) at low temperature.

Abstract

Narrow-gap higher mobility semiconducting alloys In_{1-x}Mn_{x}Sb were synthesized in polycrystalline form and their magnetic and transport properties have been investigated. Ferromagnetic response in In_{0.98}Mn_{0.02}Sb was detected by the observation of clear hysteresis loops up to room temperature in direct magnetization measurements. An unconventional (reentrant) magnetization versus temperature behavior has been found. We explained the observed peculiarities within the frameworks of recent models which suggest that a strong temperature dependence of the carrier density is a crucial parameter determining carrier-mediated ferromagnetism of (III,Mn)V semiconductors. The correlation between magnetic states and transport properties of the sample has been discussed. The contact spectroscopy method is used to investigate a band structure of (InMn)Sb near the Fermi level. Measurements of the degree of charge current spin polarization have been carried out using the point contact Andreev reflection (AR) spectroscopy. The AR data are analyzed by introducing a quasiparticle spectrum broadening, which is likely to be related to magnetic scattering in the contact. The AR spectroscopy data argued that at low temperature the sample is decomposed on metallic ferromagnetic clusters with relatively high spin polarization of charge carriers (up to 65% at 4.2K) within a cluster.