Influence of A-site disorder on the half-doped manganites.

The electronic transport and magnetism in half-doped Nd0.50Ca0.25Sr0.25MnO3 manganites have been investigated. Contrary to general half-doped system, it only displays a paramagnetic-ferromagnetic phase transition associated with an insulator-metal transition instead of with any features of charge ordering. With the decrease of temperature, an electronic phase separation and spin glass state occur in low temperature. We suggest that the A-site cation disorder induced by the size mismatch between Sr2+ ion and Ca2+ ion is mainly responsible for this phenomenon. [ABSTRACT FROM AUTHOR]