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arXiv · 1611.09458

Diagonal magnetoelectric susceptibility and effect of Fe-doping in a polar ferrimagnet Mn2Mo3O8

T. Kurumaji·S. Ishiwata·Y. Tokura
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Abstract

We investigate a large variation in a diagonal component of the linear magnetoelectric (ME) susceptibility in a polar ferrimagnet Mn2Mo3O8 while changing the magnetic-ion site from orbital-quenched Mn2+ to Fe2+ with strong uniaxial anisotropy. In Mn2Mo3O8, the linear ME susceptibility is dominated by the non-relativistic exchange striction mechanism, showing a positive value at low temperature and a critical behavior toward negative divergence around the transition temperature. This negative peak value becomes four times larger when 50% of Mn2+ ions are replaced with Fe2+ ion, highlighting the beneficial perspective of the compositionally-tunable ME effect. As the doped Fe increases in fraction, gradual negative shift of the ME coefficient is observed around the lowest temperature, which manifests relativistic single-site origin of the ME susceptibility. Further doping with x >= 75% in (Mn1-xFex)2Mo3O8, the ME coefficient becomes negative in the entire temperature region. Such a composition dependence can be explained in terms of the chemical preference for the two types of magnetic sites of Mn/Fe ions. The present study demonstrates the large tunability of ME effect by substituting the magnetic ion with the primary structural/magnetic characters kept intact.

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T. Kurumaji, S. Ishiwata, Y. Tokura. 2016-11-29. Diagonal magnetoelectric susceptibility and effect of Fe-doping in a polar ferrimagnet Mn2Mo3O8. https://doi.org/10.1103/physrevb.95.045142

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