Mn NMR observation of colossal magnetoresistance effect in SmSrMnO.

Temperature dependent Mn NMR study of SmSrMnO is reported. Previous bulk magnetization measurements have shown that below T ~ 125 K the sample is ferromagnetic metallic (FMM) and above T it is charge ordered and insulating. In present report, we show that from zero-field NMR a single line double-exchange (DE) signal is observed at temperatures up to 139 K, which is due to a presence of FMM clusters also above T .

Effect of surface polishing and oxidization induced strain on electronic order at the Verwey transition in Fe3O4.

Following the controversy between two previous publications (Lorenzo et al 2008 Phys. Rev. Lett.