Structural, electronic and magnetic properties of Sc3+ doped CoCr2O4 nanoparticles. (12th August 2020) - Manjunatha, K.
Abstract : Experimental and theoretical analyses were combined to reveal the major properties of Co1− x Sc x Cr2 O4 nanoparticles – a putative candidate for magnetic applications. Abstract : The control over spin distribution to achieve magnetic properties in crystalline structures is crucial for materials design. A clear understanding of the relationship between structure and properties is essential for the development of magnetic materials. Herein, we investigate the effect of Sc-doping on the structural, electronic, and magnetic properties of Co1− x Sc x Cr2 O4 ( x = 0.0 and 0.05) nanoparticles synthesised by a solution combustion method and perform in-depth DFT calculations to clarify the spin distribution and magnetic states. The synthesized samples showed a single phase of the spinel cubic structure. Structural distortions associated with the creation of A-site vacancies originate from overall deformations of the tetrahedral [CoO4 ] and octahedral [CrO6 ] clusters. Aiming to understand the magnetic behavior of the sintered samples, temperature-dependent susceptibility and field-dependent magnetization studies were conducted, revealing two magnetic transitions defined as paramagnetic collinear ferrimagnetic (FIM) ( T C ) and non-collinear spiral FIM ( T S ) states. Further, upon Sc-doping of the [CoO4 ] cluster, T C and T S decreased because of structural defects acting directly on the exchange coupling constants. The modification resulted in an enhancement of A–B and B–B antiferromagnetic (AFM) interactions, deeply clarified by DFT calculations. Hence, our experimental and theoretical approach uncovers a Sc-doping mechanism able to control the CoCr2 O4 magnetic properties of the matrix using structural distortions and long-range spin ordering.