The metal-insulator transition temperature in CMR manganites has been altered and brought close to the room temperature by preparing La$_{ 0.67}$Sr$_{ 0.33}$MnO$_{ 3}$ (LSMO)/ Nd$_{ 0.67}$Sr$_{ 0.33}$MnO$_{ 3}$ (NSMO) multilayers with ultra thin individual layers of LSMO and NSMO. The LSMO/NSMO multilayers with ultra thin individual layers of thickness of about $10\AA$ exhibits 150% magnetoresistance at 270 K whereas LSMO/NSMO multilayers with moderate individual layer thickness of about $40\AA$ each exhibits a mere 15% magnetoresistance at the same temperature. We have shown that the reduction in thickness of the individual layers leads to increased spin fluctuation which results in the enhancement of magnetoresistance.
Categories: cond-mat.mes-hall cond-mat.mtrl-sci