Enhancement of ferromagnetism upon thermal annealing in pure ZnO

2007/02/21 by S. Banerjee, M. Mandal, Banerjee, S. +5
Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #cond-mat.mtrl-sci

paper · pdf · doi:10.48550/arxiv.cond-mat/0702486

4 figures

arxiv created 2007/09/25 · arxiv updated 2009/12/01

Abstract

We report here enhancement of ferromagnetism in pure ZnO upon thermal annealing with the ferromagnetic transition temperature Tc above room temperature. We observe a finite coercive field upto 300K and a finite thermoremanent magnetization upto 340K for the annealed sample. We propose that magnetic moments can form at anionic vacancy clusters. Ferromagnetism can occur due to either superexchange between vacancy clusters via isolated F+ centers, or through a limited electron delocalization between vacancy clusters. Isolated vacancy clusters or isolated F+ centers give rise to a strong paramagnetic like behaviour below 10K.

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