Interplay of Bound Magnetic Polaron and p-d exchange interaction in Co-doped 3C-SiC

TL;DR

This study provides experimental evidence of bound magnetic polarons and defect-induced ferromagnetism in Co-doped 3C-SiC, revealing high Curie temperatures and the role of exchange interactions in magnetic behavior.

Contribution

It demonstrates the role of bound magnetic polarons and defects in inducing room temperature ferromagnetism in Co-doped 3C-SiC, supported by experimental magnetic and EPR data.

Findings

Room temperature ferromagnetism in all doped samples

Curie temperature above 800 K in Co-doped 3C-SiC

Magnetic interactions explained by BMP model involving Co2+ and defects

Abstract

Bound Magnetic Polarons (BMP) have been proposed to play an important role in doped wide band gap semiconductors. We report the experimental evidence supporting polaronic magnetism and the role of defects on it. Temperature variation of electron paramagnetic resonance study reveals that the valence state of cobalt is 2+ and its nearest environment in the system is distorted tetrahedral in nature. Room temperature ferromagnetism have been found in all the doped [Co (1, 3, 5) % doped 3C-SiC] samples. The Curie temperature, TC of the samples have been found to be above 800 K. The isothermal magnetization plots, to determine the strength of domain wall pinning were analyzed using the Jiles-Atherton Model. The temperature variation of the anisotropic constant was determined using Law of Approach to saturation (LAS), which decreases with increase in temperature. Quantitative analysis of magnetic interaction has been carried out and the result is explained by using BMP Model, which probably arises out of the exchange interaction of Co2+ ions with related (Si, C) defects.