Mössbauer and magnetization studies of magnetic phase transitions in 0.5BiFeO3–0.5NaNbO3 and 0.5LaFeO3–0.5NaNbO3 solid solutions

Abstract

0.5AFeO3–0.5NaNbO3 (A=Bi, La) solid solution compositions were prepared using a solid phase reaction route from high-purity starting oxides. Mössbauer studies have shown that while for 0.5BiFeO3–0.5NaNbO3 the magnetic phase transition temperature TM value is about 150K, for 0.5LaFeO3–0.5NaNbO3, it is only ≈25K. This dramatic difference in TM values seems to be due to additional contribution of the magnetic superexchange between Fe3+ ions via the empty 6p-states of Bi3+ ions to the overall superexchange.

Keywords

• multiferroic
• magnetic phase transition
• bifeo3
• magnetic superexchange