Suppression of hole-mediated ferromagnetism in GaMnP by hydrogen

TL;DR

This study demonstrates that hydrogen passivation effectively suppresses hole-mediated ferromagnetism in GaMnP by increasing resistivity and inducing paramagnetism, confirming the role of carriers in ferromagnetic behavior.

Contribution

It provides direct experimental evidence that ferromagnetism in GaMnP is carrier-mediated and shows hydrogenation as a method to control magnetic properties.

Findings

Resistivity increases by three orders of magnitude after hydrogenation.

Hydrogenated samples become paramagnetic at low temperatures.

Ferromagnetism is confirmed to be carrier-mediated in GaMnP.

Abstract

We report the successful passivation of the Mn acceptors in GaMnP upon exposure to a remote dc hydrogen plasma. The as-grown films are non-metallic and ferromagnetic with a Curie temperature of T_C=55K. After hydrogenation the sample resistivity increases by approximately three orders of magnitude at room temperature and six orders of magnitude at 25 K. Furthermore, the hydrogenated samples are paramagnetic, which is evidenced by a magnetization curve at 5 K that is best described by a Brillouin function with g=2 and J=5/2 expected for Mn atoms in the 3d^5 configuration. These observations unambiguously proof that the ferromagnetism is carrier-mediated also in GaMnP.