Refinement of the Atomic and Magnetic Structures of Solid Solutions BaFe12 – xInxO19 (x = 0.1–1.2) by the Neutron Diffraction Method

Аннотация

Structural investigations of solid solutions of BaFe_12 – xIn_xO₁₉ barium ferrites partially substituted with indium ions (x = 0.1–1.2) are carried out via the neutron diffraction method. Experimental investigations of ceramic samples are performed at room temperature using a high-resolution neutron diffractometer that allows precise information about changes in the crystal and magnetic structures, as well as microstructural parameters, to be obtained. Refinement of the crystal structure of the composition BaFe_12 – xIn_xO₁₉ is carried out in the framework of two space groups P6₃/mmc and Р6₃mc. Solid solutions of barium ferrites retain the hexagonal crystal-structure type in the entire investigated concentration range. Their ferrimagnetic structure is well described by Gorter’s model where magnetic moments are ordered along the c axis. Spontaneous polarization is revealed in barium hexaferrites partially substituted with indium ions. The total magnetic moment per formula unit decreases as the amount of diamagnetic In ions is increased. An increase in microstrains in the crystallites with increasing amount of In ions is explained by increasing disorder of the system because of the statistical distribution of diamagnetic ions in magnetic sublattices.