Enhanced low-field magnetization and magnetoresistance in nano-MgO added La2/3Ca1/3MnO3 composites

摘要

We report the significant enhancement of low-field magnetization and magnetoresistance (MR) in La2/3Ca1/3MnO3 (LCMO) compounds with 5 at.% nano-MgO addition in the form of both nanoparticle and nanowire. It is found that the magnetization of the nano-MgO added compounds is highly sensitive to a low applied field below 7 kOe compared with the MgO-free LCMO. In addition, the enhancement of low-field MR is found in nano-MgO added compounds and the enhancement for the nanowire MgO-added composite is more remarkable than that for the nanoparticle MgO-added one. Moreover, two ferromagnetic phases with low-T-C and high-T-C in nano-MgO added compounds are observed. These results demonstrate that the low-field transport and magnetic properties of LCMO compounds can be effectively manipulated by controlling the morphology and dispersion of the insulating barrier using nano-MgO addition.