Anomalous Hall effect in insulating Ga1-xMnxAs

TL;DR

This study explores how Te doping affects the anomalous Hall effect and magnetic properties in insulating Ga1-xMnxAs with x=0.085, revealing the suppression of ferromagnetism and transition to spin glass behavior.

Contribution

It provides experimental insights into the impact of Te doping on the anomalous Hall effect and magnetic phase transitions in Ga1-xMnxAs at high Mn concentration.

Findings

Te doping decreases Curie temperature.

Increased Te leads to disappearance of ferromagnetic order.

Paramagnetic-to-spin glass transition observed.

Abstract

We have investigated the effect of doping by Te on the anomalous Hall effect in Ga1-xMnxAs (x = 0.085). For this relatively high value of x the temperature dependence of resistivity shows an insulating behavior. It is well known that in Ga1-xMnxAs the Mn ions naturally act as acceptors. Additional doping by Te donors decreases the Curie temperature and increases the anomalous Hall resistivity. With increasing Te concentration the long-range ferromagnetic order in Ga1-xMnxAs eventually disappears, and paramagnetic-to-spin glass transition is observed instead. The critical concentration of holes required for establishing ferromagnetic order in Ga1-xMnxAs (x = 0.085) has been estimated by using the magnetic polaron percolation theory proposed by Kaminski and Das Sarma [Phys.Rev.Lett. 88, 247202 (2002)].