Above-Room-Temperature Ferromagnetism in GaSb/Mn Digital Alloys

TL;DR

This study demonstrates that GaSb/Mn digital alloys exhibit ferromagnetism and a strong anomalous Hall effect up to 400 K, with high crystal quality and metallic conductivity, promising for spintronics applications.

Contribution

It reports the fabrication and characterization of GaSb/Mn digital alloys showing room-temperature ferromagnetism and anomalous Hall effect without MnSb precipitates.

Findings

Ferromagnetism observed up to 400 K.

Strong anomalous Hall effect correlates with magnetization.

Samples exhibit metallic p-type conductivity.

Abstract

Digital alloys of GaSb/Mn have been fabricated by molecular beam epitaxy. Transmission electron micrographs showed good crystal quality with individual Mn-containing layers well resolved; no evidence of 3D MnSb precipitates was seen in as-grown samples. All samples studied exhibited ferromagnetism with temperature dependent hysteresis loops in the magnetization accompanied by metallic p-type conductivity with a strong anomalous Hall effect (AHE) up to 400 K (limited by the experimental setup). The anomalous Hall effect shows hysteresis loops at low temperatures and above room temperature very similar to those seen in the magnetization. The strong AHE with hysteresis indicates that the holes interact with the Mn spins above room temperature. All samples are metallic, which is important for spintronics applications. * To whom correspondence should be addressed. E-mail: luo@buffalo.edu