Strong ferromagnetic-dielectric coupling in multiferroic Lu ₂CoMnO₆ single crystals

We have grown single crystals of multiferroic double-perovskite Lu ₂CoMnO₆ and studied the directional dependence of their magnetic and dielectric properties. The ferromagnetic order emerges below T _C ≈ 48 K along the crystallographic c axis. Dielectric anomaly arises along the b axis at T_C, contrary to the polycrystalline work suggesting ferroelectricity along the c axis. Through the strongly coupled ferromagnetic and dielectric states, the highly non-linear variation of both dielectric constant and magnetization was achieved in application of magnetic fields. This concurrent tunability provides an efficient route to manipulation of multiple order parameters in multiferroics.