Size-induced metal insulator transition and glassy magnetic behavior in La0.5Sr0.5CoO3 nanoparticles

Structural, electrical, and magnetic properties of La0.5Sr0.5CoO3 nanoparticles prepared by sol-gel technique are investigated and the results reveal a size-induced metal insulator transition in the electrotransport behavior. The field cooled and zero field cooled magnetizations display a broad paramagnetic to ferromagnetic transition at T-c with a large magnetic irreversibility. Attempts are made to get an idea about the spin states in the nanoparticles. The observed frequency dependent shoulder in the in-phase (chi(')) component and the peak in the out of phase (chi '') component of the ac susceptibility in the low temperature region indicate the glassy nature of the samples. (c) 2008 American Institute of Physics.