Real-space imaging of magnetic phase transformation in single crystalline Sm-Ca-Sr based manganite compound

Low-temperature-high-magnetic field magnetic force microscopy studies on colossal magnetoresistance material Sm_0.5Ca_0.25Sr_0.25MnO₃have been carried out. These measurements provide real-space visualization of antiferromagnetic-ferromagnetic (AFM-FM) transition on sub-micron length scale and explain the presence of AFM-FM transition in the temperature-dependent magnetization measurements, but the absence of corresponding metal-insulator transition in temperature-dependent resistivity measurements at the low magnetic field. Distribution of transition temperature over the scanned area indicates towards the quench disorder broadening of the first-order magnetic phase transition. It shows that the length scale of chemical inhomogeneity extends over several micrometers.