Electrical transport and ferromagnetism in Ga1-xMnxAs synthesized by ion implantation and pulsed-laser melting

TL;DR

This study investigates the magnetic and electrical properties of Ga1-xMnxAs films synthesized by ion implantation and pulsed-laser melting, revealing intrinsic ferromagnetism and transport characteristics similar to those grown by molecular beam epitaxy.

Contribution

It demonstrates that ion implantation combined with pulsed-laser melting produces high-quality ferromagnetic Ga1-xMnxAs films with properties comparable to traditional growth methods, free from interstitial Mn.

Findings

Strong p-d interaction signatures observed.

Good agreement with LT-MBE films with similar Mn content.

Films are free from interstitial Mn due to high-temperature processing.

Abstract

We present a detailed investigation of the magnetic and magnetotransport properties of thin films of ferromagnetic Ga1-xMnxAs synthesized using ion implantation and pulsed-laser melting (II-PLM). The field and temperature-dependent magnetization, magnetic anisotropy, temperature-dependent resistivity, magnetoresistance, and Hall effect of II-PLM Ga1-xMnxAs films have all of the characteristic signatures of the strong p-d interaction of holes and Mn ions observed in the dilute hole-mediated ferromagnetic phase. The ferromagnetic and electrical transport properties of II-PLM films correspond to the peak substitutional Mn concentration meaning that the non-uniform Mn depth distribution is unimportant in determining the film properties. Good quantitative agreement is found with films grown by low temperature molecular beam epitaxy (LT-MBE) and having the similar substitutional Mn_Ga composition. Additionally, we demonstrate that II-PLM Ga1-xMnxAs films are free from interstitial Mn_I because of the high temperature processing. At high Mn implantation doses the kinetics of solute redistribution during solidification alone determine the maximum resulting Mn_Ga concentration. Uniaxial anisotropy between in-plane [-110]and [110] directions is present in II-PLM Ga1-xMnxAs giving evidence for this being an intrinsic property of the carrier-mediated ferromagnetic phase.