We follow the step-by-step progression of events while approaching the Curie temperature TC from below using 57Co substituent as a microprobe in an emission Mössbauer study combined with resistivity measurements. In the temperature range 0.33 < T/TC ≤ 1, the material consists of a mixture of ferromagnetic and paramagnetic regions within the same matrix. An increase of the amount of paramagnetic fraction is accompanied by a decrease in electron delocalization in the ferromagnetic regions. At T ≥ TC, the electrons are localized to neighboring Mn4+/Mn3+ pairs only, in about 46% of the paramagnetic species. The strength with which Mn atoms are bound to the neighbors also decreases progressively and rather steeply in the range 0.65 ≤ T/TC = 1. Zero field resistivity, ρ0, follows linearly with the amount of the paramagnetic phase in the range 0.65 ≤ T/TC ≤ 1 and still shows metal-like behavior up to T/TC = 1.03.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)