The structural, phonon, magnetic, dielectric, and magneto dielectric responses of the pure bulk Brownmillerite compound Ca2FeCoO5 are reported. This compound showed giant magneto dielectric response (10%-24%) induced by strong spin-lattice coupling across its spin reorientation transition (150-250 K). The role of two Debye temperatures pertaining to differently coordinated sites in the dielectric relaxations is established. The positive giant magneto-dielectricity is shown to be a direct consequence of the modulations in the lattice degrees of freedom through applied external field across the spin reorientation transition. Our study illustrates novel control of magneto-dielectricity by tuning the spin reorientation transition in a material that possess strong spin lattice coupling.
@article{arxiv.1811.00404,
title = {Spin-lattice coupling mediated giant magnetodielectricity across the spin reorientation in Ca2FeCoO5},
author = {Gaurav Sharma and Shekhar Tyagi and V. R. Reddy and A. M. Awasthi and R. J. Choudhary and A. K. Sinha and Vasant Sathe},
journal= {arXiv preprint arXiv:1811.00404},
year = {2019}
}