Magnetic clusters in Nd1-xSrxMnO3 (0.3≤x≤0.5):: An electron-spin resonance study

The paramagnetic electron-spin resonance (ESR) linewidth of polycrystalline Nd1-xSrxMnO3 (x=0.3, 0.33, 0.4, and 0.5) increases in a quasilinear manner up to 400 K due to the formation of paramagnetic clusters, which is also confirmed by the observation of an activated behavior of the ESR intensity above T-C. Upon cooling, a pair of ferromagnetic resonance lines appear well above the magnetic transition temperature (T-C, T-N) in all cases. This suggests the presence of ferromagnetic clusters at a temperature T*>T-C. The two-line structure below T* is discussed in terms of phase separation and formation of magnetic clusters and their coexistence with a charge-ordered phase for x>0.4. (C) 2003 American Institute of Physics.