Role of boundaries on low-field magnetotransport properties of La _0.7Sr_0.3MnO₃-based nanocomposite thin films

The effects of boundaries such as grain boundaries and phase boundaries on low-field magnetoresistance (LFMR) have been investigated in single-phase lanthanum strontium manganates, in this case La0.7Sr0.3MnO3 (LSMO) and LSMO: zinc oxide (ZnO) nanocomposite thin films. I. The pure LSMO films with similar grain size, it is found tha. The LFMR increases a. The grain misorientation factor (β) increases. The LFMR i. The nanocomposite films is greatly enhanced, as compared with single-phase films, due t. The reduced grain size, and increased phase boundary (PB) and β effects. The composition study shows tha. The LFMR can be dramatically enhanced whe. The secondary phase content approache. The percolation threshold. The increased β and secondary phase concentration reduc. The cross-section of electron conduction paths and favo. The formation o. The quasi-one-dimensional transport channels. Our results demonstrate tha. The reduction of cross-section o. The electron conduction paths by tunin. The grain orientation and secondary phase composition is necessary for enhancing LFMR effect.