Kondo-like electronic transport and ferromagnetic cluster-glass behavior in La0.7Sr0.3MnO3 nanostructures

摘要

We have studied the electronic transport and magnetic properties of a nanocrystalline La0.7Sr0.3MnO3 system. The samples were prepared by sol-gel method and were sintered at different temperatures to achieve few nanometre grain sizes. The temperature dependent resistivity revealed Kondo like electronic transport at low temperature (T < 50 K) and variable range hopping in the paramagnetic insulating regime under zero and high magnetic field. The reduced grain size sample showed marginal increase in electrical resistivity. The temperature-field dependent ac-susceptibility measurement indicated the FM-cluster formation. A neck like magnetic hysteresis loop was observed due to the competition between ferromagnetic core and paramagnetic shell. The ferromagnetic clusters with paramagnetic interfaces impart glassy behavior.