Electron microscopy, X-Ray diffraction and Mossbauer studies of PbFe_0.5Nb_0.5O₃, PbFe_0.5Ta_0.5O₃ and BaFe_0.5Nb_0.5O₃ ceramics sintered from mechanoactivated nanopowders

ABSTRACT

The effect of high-energy mechanical activation on magnetic phase transition temperature T_M of PbFe_0.5Nb_0.5O₃, PbFe_0.5Ta_0.5O₃, and BaFe_0.5Nb_0.5O₃ perovskites has been studied. Mossbauer studies have shown that T_M values in all the perovskites studied can be changed substantially by mechanical activation and subsequent annealing. The increase of T_M by 40-50 K, as compared to corresponding single crystals and ceramics sintered from the non-activated powders, was achieved in the mechanoactivated powders of both lead-containing and lead-free perovskites studied.

KEYWORDS:

• Iron-containing perovskites
• mechanical activation
• Mossbauer ⁵⁷Fe spectra
• phase transition

Funding

This study is partially supported by the Russian Foundation for Basic Research (RFBR) project 13-03-00869_a, Ministry of Education and Science of the Russian Federation (research projects 2132 and 3.1137. 2014K), Southern Federal University (grant 213.01-2014/012-VG), and Research Committee of the University of Macau under Research & Development Grant for Chair Professor No RDG007/FST-CHD/2012.