Room temperature ferromagnetic-like behavior in Mn-implanted and post-annealed InAs layers deposited by Molecular Beam Epitaxy

TL;DR

This study demonstrates that Mn-implanted InAs layers exhibit room-temperature ferromagnetic-like behavior after rapid thermal annealing, likely due to MnO2 phase formation, with implications for spintronic applications.

Contribution

It reveals that short thermal treatment induces ferromagnetic-like behavior in Mn-implanted InAs, linked to MnO2 phase segregation, advancing understanding of magnetic properties in DMS materials.

Findings

Room-temperature ferromagnetic-like behavior appears after RTA.

Mn atoms are no longer substitutional after annealing.

Segregation of MnO2 phase correlates with ferromagnetism.

Abstract

We report on the magnetic and structural properties of Ar and Mn implanted InAs epitaxial films grown on GaAs (100) by Molecular Beam Epitaxy (MBE) and the effect of Rapid Thermal Annealing (RTA) for 30 seconds at 750C. Channeling Particle Induced X- ray Emission (PIXE) experiments reveal that after Mn implantation almost all Mn atoms are subsbtitutional in the In-site of the InAs lattice, like in a diluted magnetic semiconductor (DMS). All of these samples show diamagnetic behavior. But, after RTA treatment the Mn-InAs films exhibit room-temperature magnetism. According to PIXE measurements the Mn atoms are no longer substitutional. When the same set of experiments were performed with As as implantation ion all of the layers present diamagnetism without exception. This indicates that the appearance of room-temperature ferromagnetic-like behavior in the Mn-InAs-RTA layer is not related to lattice disorder produce during implantation, but to a Mn reaction produced after a short thermal treatment. X-ray diffraction patterns (XRD) and Rutherford Back Scattering (RBS) measurements evidence the segregation of an oxygen deficient-MnO2 phase (nominally MnO1.94) in the Mn-InAs-RTA epitaxial layers which might be on the origin of room temperature ferromagnetic-like response observed.