Anisotropy in the magnetization and magnetoelectric response of single crystalline Mn4Ta2O9

Abstract

We report temperature dependent magnetization and neutron diffraction measurements on the corundum related magnetoelectric antiferromagnet Mn4Ta2O9. Measurements performed on a single crystalline specimen reveal that the magnetization is anisotropic, and a weak ferromagnetic component emerges well within the antiferromagnetically ordered state. Powder neutron diffraction measurements indicate that the magnetic structure comprises of antiferromagnetically coupled ferromagnetic chains of Mn2+ spins aligned along the trigonal c axis, in contrast to that reported in other isostructural members of this family. Magnetic measurements performed under a periodic electric field indicate that the magnetoelectric response is also anisotropic, with this coupling along the trigonal c axis and that perpendicular to it having different signs.