Electronic structure of substitutional Mn in epitaxial In0.965Mn0.035Sb film

Abstract

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.

High-temperature ferromagnetism in epitaxial (In,Mn)Sb films

“…Further evidence for the absence of hex-MnSb in MOVPE InMnSb films has been demonstrated by recent x-ray magnetic circular dichroism ͑XMCD͒ studies. 28 A clear difference in the XMCD line shape of MOVPE InMnSb and hex-MnSb films is measured, which arises due to the difference in crystal symmetry and coordination of Mn. Thus if present, it has been proposed that MnSb could be potentially incorporated as clusters with tetrahedral symmetry although MnSb in a zinc blende structure is metastable.…”

Magnetotransport properties of InMnSb magnetic semiconductor thin films

“…X-ray diffraction ͑XRD͒ and high-resolution transmission electron microscopy ͑TEM͒ indicate that the films are single phase with no secondary phases present. 21 In addition, extended x-ray absorption fine-structure ͑EXAFS͒ analysis indicates that Mn substitutes for In and has tetrahedral coordination as would be expected for a single-phase film with a zinc-blende structure. [20][21][22] Magnetic properties of the films were measured with a superconducting quantum interference device ͑SQUID͒ magnetometer.…”

“…21 In addition, extended x-ray absorption fine-structure ͑EXAFS͒ analysis indicates that Mn substitutes for In and has tetrahedral coordination as would be expected for a single-phase film with a zinc-blende structure. [20][21][22] Magnetic properties of the films were measured with a superconducting quantum interference device ͑SQUID͒ magnetometer. For analysis, the diamagnetic contribution from the substrate and holder was subtracted from the total sample magnetization.…”

“…It is worth noting that the disappearance of the negative magnetoresistance above 10 K does not represent a magnetic transition from ferromagnetic to paramagnetic states as the T C for the two films grown under identical conditions was found to be in excess of 400 K from both SQUID magnetometry and magnetic force microscopy. 21 To determine the scattering mechanisms responsible for the observed low-temperature magnetoresistance shown in Fig. 2, we performed a least-squares fitting of our data to the expression given by…”

“…Furthermore, ZFC and FC magnetization versus temperature curves show clear reversibility and thus support the homogenous nature of ferromagnetism in the films at room temperature. 20,21 It has been recently proposed that the ferromagnetism in InMnSb is stabilized by a Ruderman-Kittel-Kasuya-Yosida mechanism and with correlated substitution of magnetic impurities. 43,44 In this case, substitutional Mn acceptor complexes are the source of both free holes and the localized spins that lead to a high T C .…”