Please use this identifier to cite or link to this item: http://dspace.iitrpr.ac.in:8080/xmlui/handle/123456789/4316
Title: Spin and valence variation in cobalt doped barium strontium titanate ceramics
Authors: Kaur, A.
Singh, D.
Das, A.
Asokan, K.
Chen, C.-L.
Mishra, I.B.
Ahuja, R.
Issue Date: 19-Dec-2022
Abstract: In the present decade, owing to half-metallic ferromagnetism, controlled 3d transition metal-doping based defect engineering in oxide perovskites attracts considerable attention in the pursuit of spintronics. We aim to investigate the electronic structure of Co-doped barium strontium titanate (Ba0.8Sr0.2CoxTi1−xO3 where x = 0, 0.1, 0.2) solid solution. Structural, vibrational and microscopic properties indicate the cationic substitution of Co at the octahedral Ti position along with a displacive kind of tetragonal-to-cubic phase transformation. X-ray photoelectron spectroscopy evidences the reduction in the valence state from Co3+ to Co2+ and Ti K edge X-ray absorption spectroscopy endorses the higher lattice symmetry with increasing Co doping. Orbital hybridization triggered electron hopping between O 2p and Co eg orbitals results in a spin fluctuation from the occupation t62ge0g for x = 0.1 to the occupation t62ge1gL for x = 0.20 (L designates a hole in the O 2p shell) aligned state observed from density functional theory calculations. The dominating crystal field energy as compared to intra-atomic exchange (Hund) energy decides the spin-orbital degeneracy for the Co 3d orbital to induce spin fluctuations.
URI: http://localhost:8080/xmlui/handle/123456789/4316
Appears in Collections:Year-2022

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