The effect of A-site chemical disorder on the ferromagnetic transition and spin dynamics for the magnetoresistive perovskite La0.54 Ba 0.46 MnO3 were discussed. It was found that the disorder reduced exchange interactions by only 9% that were revealed by low temperature spin waves. It was also found that the transition was discontinuous in the disordered sample with the development of a quasielastic peak in the spectrum below TC and long time relaxation of the order parameter. The results show that the chemical disorder lowered the energy for polaron formation in manganese perovskites and was the origin of 50 K reduction in TC.
ASJC Scopus subject areas
- Physics and Astronomy(all)