F+ center exchange mechanism and magnetocrystalline anisotropy in Ni-doped 3C-SiC

Abstract

• F + center exchange mechanism has been invoked in order to explain the long range magnetic order in the system. • The Curie temperature is found to be above 350 K for all the doped samples obtained from the modified Bloch’s T 3/2 law. • The dynamic nature of the BMPs sizes have been studied extensively using Hc vs T data. • The spontaneous spin polarization has been induced in the system due to strong hybridization between (C) 2p and (Ni) 3d orbital. • The decrease in magneto crystalline anisotropy constant value with increase in temperature essentially indicates the weakening of the magnetic interaction in the system. • The incomplete quenching of orbital angular momentum and partial removal of orbital degeneracy resulted in reduction of line width and enhancement of integrated intensity as the temperature rises. Towards the development of a magnetic semiconductor suitable for spintronic device applications in extreme environments, we explored the possibility of inducing magnetic interaction in SiC by doping Nickel. The X-ray diffraction and Raman Spectroscopy studies confirm the incorporation of Ni into the host lattice. The magnetic measurements and electron spin resonance studies indicate the presence of room temperature ferromagnetic interaction in the system. The Curie temperature of 1, 3, and 5% Ni-doped samples have been found to be 420 K, 520 K, and 540 K respectively. Electron spin resonance study reveals that the valence state of Ni is 2 + , which implies the creation of vacancies at both Silicon (V Si ) and Carbon (V C ) sites as they are tetravalent. The change in magnetization of the system with an increase in dopant concentration is consistent with the variation in the number of vacancies and free holes. The analysis of magnetization data using the Law of approach to saturation shows that the anisotropic constant decreases with an increase in temperature. The long-range magnetic interaction in the system is explained using the F + center exchange mechanism.