Powder Neutron Diffraction studies of Ca1-xDyxBaFe4O7 (x <= 0.03)

Recent studies of CaBaFe4O7 highlight the attractive functional properties of these materials such as gigantic electric polarization, large magnetization and strong magnetoelectric coupling. These are also fundamentally important because of competing magnetic interactions due to geometrical frustration in the alternately arranged two dimensional kagomé and triangular layers of Fe tetrahedra. This proposal concentrates on the study of Dy-doped CaBaFe4O7 that show drastic changes in the magnetic ground state upon only a slight doping of 1 – 3% at the Ca site. The transition temperature of 3% doped sample shifts to 385 K from 274 K which is substantiated by a neutron powder diffraction data at room temperature revealing a magnetic structure different from the parent compound. In order to completely investigate the effects of this doping on the magnetic structure, we propose neutron powder diffraction studies at various temperatures. The aim is to clearly point out the nature of magnetism and the origin of magnetoelectric coupling.