Enhanced magnetoresistance of multilayered thin films prepared by pulsed laser deposition

摘要

La_(0.7)Sr_(0.3)MnO_3/iron oxide multilayered thin films are prepared by alternatively laser-ablating a La_(0.7)Sr_(0.3)MnO_3 (LSMO) ceramic and pure Fe targets on silicon wafers. The electro- and magneto-transport properties and low-field magnetoresistance (LFMR) of the as-grown multilayers of different iron oxide thickness are evaluated. It is revealed that the ultra-thin iron oxide layer as the insulator separating the conductive LSMO layers benefits to the enhanced magnetoresistance, which decreases, however, with further increasing of the iron oxide layer thickness. It is suggested that the iron oxide layers between LSMO act as the insulator for electron tunneling. The spin-polarized tunneling is considered as the probable conduction mechanism.