Enhancement of weak magnetism of 3C-SiC by 3d-transition metal doping

Abstract

Defects seem to play a very decisive role in setting up long-range magnetic order in 3C-SiC. The feeble ferro-magnetic response exhibited by SiC at room temperature, known as d0 magnetism, has been attributed to defects in the system. We present the strengthening of d0 magnetism through hole doping by 3d-transition metal (TM) substitution at the Si site. The valence state of the Mn, Co, and Ni has been found to be 2+ while Cr takes a 3+ valence state. The Mn-doped system exhibits the highest Curie temperature, saturation magnetization, and spontaneous magnetization value as compared to samples with other dopants. Detailed quantitative analysis of magnetization data and electron spin resonance spectra suggests the enhancement of the d0 magnetism due to the generation of holes caused by the TM doping at the Si site. The room temperature ferromagnetic response observed in the doped samples could be explained using modified Bound Magnetic Polaron (BMP) model.