Tuning of ferromagnetism through anion substitution in Ga-Mn-pnictide ferromagnetic semiconductors

TL;DR

This study demonstrates how anion substitution in Ga-Mn-pnictide ferromagnetic semiconductors influences magnetic anisotropy and Curie temperature, revealing strain effects and hole localization impacts.

Contribution

It introduces a method to tune ferromagnetism via anion substitution and strain engineering in Ga-Mn-pnictide semiconductors.

Findings

Magnetic easy axis realigns from in-plane to out-of-plane due to anion substitution.

Tensile strain induces magnetic anisotropy similar to buffer layer effects.

Curie temperature decreases with increased P content, indicating hole localization.

Abstract

We have synthesized Ga1-xMnxAs1-yPy and Ga1-xMnxP1-yNy by the combination of ion implantation and pulsed-laser melting. We find that the incorporation of isovalent impurities with smaller atomic radii leads to a realignment of the magnetic easy axis in Ga1-xMnxP1-yNy/GaP and Ga1-xMnxAs1-yPy/GaAs thin films from in-plane to out-of-plane. This tensile-strain-induced magnetic anisotropy is reminiscent of that observed in Ga1-xMnxAs grown on larger lattice constant (In,Ga)As buffer layers indicating that the role of strain in determining magnetic anisotropy is fundamental to III-Mn-V materials. In addition, we observe a decrease in the ferromagnetic Curie temperature in Ga1-xMnxAs1-yPy with increasing y from 0 to 0.028. Such a decrease may result from localization of holes as the P/As ratio on the Group V sublattice increases.