Spin dynamics in Nd1-xSrxMnO3 with x=0.5

Muon spin relaxation (mu(+)SR) spectroscopy has been applied to study spin dynamics in the manganite single crystal Nd0.5Sr0.5MnO3. Critical slowing d own of Mn spin fluctuations has been observed above the ferromagnetic order ing temperature T-C similar to 251 K. The dynamic critical exponent z = 2.0 0(12), deduced from muon spin relaxation rates above T-C (nonasymptotic reg ime) agrees with the results of 3d dipolar ferromagnets. Root-exponential r elaxation is observed above 160 K and has been attributed to muon spin rela xation in local regions containing differently sized small spin clusters. ( C) 2000 Elsevier Science B.V. All rights reserved.