Epitaxial growth of diluted magnetic semiconductor Ge1-xCrxTe with high Cr composition

TL;DR

This study demonstrates the epitaxial growth of Ge1-xCrxTe layers with high Cr content, revealing ferromagnetic properties and a Curie temperature reaching 200 K, with implications for spintronic applications.

Contribution

It reports the successful epitaxial growth of Ge1-xCrxTe with high Cr composition and characterizes its magnetic properties, highlighting a different ferromagnetic mechanism from Mn-doped semiconductors.

Findings

Epitaxial Ge1-xCrxTe layers grown on SrF2 substrates.

Observation of ferromagnetism with Curie temperature up to 200 K.

Ferromagnetism mechanism appears independent of hole concentration.

Abstract

IV-VI diluted magnetic semiconductor Ge1-xCrxTe layers up to x=0.1 were grown on SrF2 substrates by molecular beam epitaxy. In site reflection high-energy electron diffraction shows a streaky pattern with sixfold symmetry in the plane for the Ge1-xCrxTe layer, implying an epitaxial growth of Ge1-xCrxTe [111]/SrF2 [111]. A clear hysteresis loop is observed in the anomalous Hall effect measurements due to the strong spin-orbit interaction in the host GeTe. The Curie temperature increases with increasing Cr composition up to 200 K, but there is no clear dependence of the Curie temperature on the hole concentration, implying that the mechanism of the ferromagnetic interaction among Cr ions is different from Mn doped diluted magnetic semiconductors.