mu+SR studies on (Nd1-ySmy)(0.5)Sr0.5MnO3

The local magnetic fields and spin dynamics of the manganite (Nd0.125Sm0.87 5)(0.52)Sr0.48MnO3 were studied using muon spin rotation/relaxation methods . In the paramagnetic phase, the relaxation time T-1 as a function of tempe rature was found to deviate from linearity below 300 K, indicating microsco pic observation of antiferromagnetic instability above the ferromagnetic tr ansition temperature T-c. In the metastable ferromagnetic metallic phase, t wo different magnetically inequivalent interstitial muon sites were observe d with hyperfine coupling constants, A(hf), of - 3.26 kG/mu(B) and - 1.27kG /mu(B), which are nearly temperature independent above 20 K. (C) 1999 Elsev ier Science B.V. All rights reserved.