Magnetic Structure and Dielectric State in the Multiferroic Ca2CoSi2O7

The magnetic structure of the multiferroic Ca2CoSi2O7 was determined by neutron diffraction techniques. A combination of experiments on polycrystalline and single-crystal samples revealed a collinear antiferromagnetic structure with the easy axis along the 〈100〉 directions. The dielectric state is discussed in the framework of the spin-dependent d–p hybridization mechanism, leading to the realization of the antiferroelectric structure. The origin of the magnetic anisotropy is discussed in comparison with that of the isostructural Ba2CoGe2O7.