Magnetic Ordering in BaFe $$_{11.9}$$ 11.9 In $$_{0.1}$$ 0.1 O $$_{19}$$ 19 Hexaferrite

Abstract

The crystal and magnetic structure by powder neutron diffractometry as well as the magnetic properties by vibration sample magnetometry for the BaFe $$_{11.9}$$ In $$_{0.1}$$ O $$_{19}$$ polycrystalline sample have been performed in a wide temperature range from 10 up to 730 K and in magnetic field up to 14 T. The atomic coordinates and lattice parameters have been Rietveld refined. The Invar effect has been observed in the low-temperature range below 150 K. It was explained by the thermal oscillation anharmonicity of atoms. The increase of the microstress value with decreasing temperature has been defined from Rietveld refinement. It is established that the ferrimagnet–paramagnet phase transition is a standard second-order one. From the macroscopic magnetization measurement, the Curie temperature and ordered magnetic moment per nominal iron ion are obtained. From the microscopic diffraction measurement, the magnetic moments at different atomic position and total magnetic moment per iron ion have been defined at different temperatures. The most likely reasons and the mechanism of magnetic ordering are discussed.