Phase separation in La0.5Ca0.5MnO3 observed by Mn-55 and La-139 NMR

We studied zero-field Mn-55 and La-139 nuclear magnetic resonance (NMR) in La0.5Ca0.5MnO3. The Mn-55 and La-139 NMR intensities, resonance frequencies , and spin-spin relaxation times showed thermal hystereses upon cooling and warming. The analysis of the result shows that there are two distinct phas e regions below T-C: a stable metallic ferromagnetic (FM) region and a regi on where metallic FM and insulating antiferromagnetic phases compete. The t wo metallic FM phases are distinguished by mobile e(g) electron density. Th e e(g) electron density of the stable FM phase is 0.5, but that of the FM p hase:in the competition region is lower than that. [S0163-1829(99)04945-0].