ESR study of spin-lattice correlated clusters in single crystalline Nd <inf>0.7</inf>Sr<inf>0.3</inf>MnO<inf>3</inf>

We report electron spin resonance measurements in single crystalline Nd0.7Sr0.3MnO3 that provide evidence for the existence of spin-lattice correlated clusters above and below TC (≤ 205K). The linewidth of the paramagnetic spectrum indicates the presence of strong electron-phonon interaction rather than the spin only interaction seen in other manganites. The gradual increase observed in the g value above T C is attributed to the presence of orbital correlations. The observation of ferromagnetic resonance (FMR) spectra only below 185K (T C ≤ 205K) and noisy features in the FMR spectra above 140K are ascribed to the strong competition between localization due to lattice distortions and delocalization of charge carriers. The magnetocrystalline anisotropy of the sample splits the FMR line into two below 185K. An additional splitting observed in the FMR line is attributed to the existence of spin-lattice correlated (insulating) clusters within the ferromagnetic (metallic) phase. The influence of these clusters on the spin dynamics above and below TC is discussed. © IOP Publishing Ltd.