Structure and magnetic properties of BaFe11.9In0.1O19 hexaferrite in a wide temperature range

The investigations of the crystal and magnetic structure by powder neutron diffractometry as well as the magnetic properties by vibration sample magnetometry for the BaFe11.9In0.1O19 polycrystalline sample have been performed in a wide temperature range from 10 K up to 730 K and in the magnetic fields up to 14 T. The atomic coordinates and lattice parameters have been Rietveld refined. The Invar effect has been observed in low temperature range below 150 K. The temperature evaluation of the main Fe-O bond lengths and Fe-O-Fe bond angles are constructed. The increase of microstress value with decreasing temperature has been defined from Rietveld refinement. 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 nature of the intrasublattice and intersublattice Fe3+-O2--Fe3+ indirect exchange interactions is investigated at the different temperatures. From the macroscopic magnetization measurement the Curie temperature and the ordered magnetic moment per nominal iron ion are obtained. It is established that the ferrimagnet-paramagnet phase transition is a standard second-order one. The magnetic structure model is proposed. The most likely reasons and the mechanism of magnetic structure formation are discussed. (C) 2016 Elsevier B.V. All rights reserved.