Enhanced tunable magnetoresistance properties over a wide temperature range in epitaxial (La0.7Sr0.3MnO3)1-x:(CeO2)x nanocomposites

Abstract

Vertically aligned nanocomposite (VAN) (La0.7Sr0.3MnO3)1-x:(CeO2)x (LSMO:CeO2) thin films have been grown on SrTiO3 (001) substrates by pulsed laser deposition. Tunable magnetoresistance properties as well as microstructures are demonstrated in these VAN films by modulating the film composition (x=0, 0.3, 0.4, 0.45, 0.5, and 0.55). The sample of x=0.3 shows a large low-field magnetoresistance (LFMR) in a high temperature range, i.e., over 10% at the range of 280K to 320K under 1T and with a peak value of ∼13.5% at 310K. In addition, a vast enhancement of LFMR in a low temperature range of 20-150K with peak of ≈34.3% at 45K for 1T could be achieved with x=0.5. The enhanced LFMR properties can be attributed to both the phase boundary induced spin fluctuation and the magnetic tunneling effect through vertical ferromagnetic/insulator/ferromagnetic structures. The observed enhanced LFMR performance, especially at high temperatures, as well as its simple growth method, offers a great potential for LSMO:CeO2nanocomposites to be used in spintronic devices in a large temperature range.