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Large Magneto-Dielectric Effects in Orthorhombic HoMnO3 and YMnO3

B. Lorenz·Y. Q. Wang·Y. Y. Sun·C. W. Chu
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Abstract

We have found a remarkable increase (up to 60 %) of the dielectric constant with the onset of magnetic order at 42 K in the metastable orthorhombic structures of YMnO3 and HoMnO3 that proves the existence of a strong magneto-dielectric coupling in the compounds. Magnetic, dielectric, and thermodynamic properties show distinct anomalies at the onset of the incommensurate magnetic order and thermal hysteresis effects are observed around the lock-in transition temperature at which the incommensurate magnetic order locks into a temperature independent wave vector. The orders of Mn3+ spins and Ho3+ moments both contribute to the magneto-dielectric coupling. A large magneto-dielectric effect was observed in HoMnO3 at low temperature where the dielectric constant can be tuned by an external magnetic field resulting in a decrease of up to 8 % at 7 Tesla. By comparing data for YMnO3 and HoMnO3 the contributions to the coupling between the dielectric response and Mn and Ho magnetic orders are separated.

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B. Lorenz, Y. Q. Wang, Y. Y. Sun, C. W. Chu. 2005-01-03. Large Magneto-Dielectric Effects in Orthorhombic HoMnO3 and YMnO3. https://doi.org/10.1103/physrevb.70.212412

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