NMR evidence of the magnetic phase separation in Pr0.5Ca0.2Sr0.3MnO3 manganite

The local ferromagnetism in Pr0.5Ca0.2Sr0.3MnO3 manganite was investigated by means of Mn-55 NMR for temperatures up to T-C=220 K. Below the ferromagn etic to antiferromagnetic transition NMR detects a minority ferromagnetic p hase, which gives rise to two NMR lines having comparable amplitudes. One o f these lines is attributed to the volume, while the other to the boundary of the ferromagnetic microdomains. For T greater than or equal to T-N anoth er line corresponding to the bulk ferromagnetism appears, which coexists wi th the signal from the minority ferromagnetic phase. All NMR signals displa y conspicuous thermal hysteresis of the amplitude, reflecting the first-ord er character of the ferromagnetic <-> antiferromagnetic transition. In addi tion a hysteresis of the frequency of the minority ferromagnetic phase sign al was also observed. The results demonstrate a specific case of the micros copic phase separation.