The crystal structure of hexagonal-Sr0.6Ba0.4MnO3 allows various competing superexchange interactions, leading to intriguing magnetic properties. Local structural changes modify overlapping between Mn and oxygen ions with temperature. Calculations based on our model spin-Hamiltonian reveal that the dominant linear antiferromagnetic superexchange interaction between the oxygen-linked Mn4+ ions results in short range correlations (SRC), manifesting a smooth drop in magnetization below 325K. Dominance of superexchange interaction changes its allegiance towards the non-linear oxygen-linked Mn-O-Mn interactions, onsetting long-range correlations (LRC) below 225K. Below the SRC-LRC crossover temperature, electrical response arising from the interacting dipoles exhibits power-law divergent behaviour of relaxation time, upon cooling. Non-ergodic character of the dipole-cluster glass state is examined via the indispensable aging and rejuvenation effects, similar to the spin glasses. Competitive-frustration among spin-exchange and local-strain is reckoned as responsible for the electrical glass origin.
@article{arxiv.1910.14446,
title = {Magneto-dielectric coupling and non-ergodic electrical behaviour in hexagonal Sr0.6Ba0.4MnO3 via local strain driven magnetic ordering},
author = {Ritu Rawat and R. J. Choudhary and A. M. Awasthi and Rajamani Raghunathan and Archna Sagdeo and A. K. Sinha and S. Chaudhary and S. Patnaik and D. M. Phase},
journal= {arXiv preprint arXiv:1910.14446},
year = {2019}
}
Comments
20 pages, 6 figures, 32 references. arXiv admin note: substantial text overlap with arXiv:1807.01303