Magnetoresistance of single-crystalline La0.67Sr0.33MnO3/MgO nanorod arrays

The La0.67Sr0.33MnO3/MgO core-shell nanorod arrays were prepared by a combination of chemical vapor deposition and pulsed laser deposition. The microscopic structure characterization demonstrated that the La0.67Sr0.33MnO3 shell phase in the nanorod is of single-crystalline quality with a uniform epitaxial registry with the MgO core templates. An enhanced negative magnetoresistance is achieved in the nanorod arrays compared to the reference La0.67Sr0.33MnO3 thin film, and the magnitude is greater than 5.48% at μ0H=1 T over a wide temperature range from 10 K to 300 K. The enhancement of magnetoresistance in the low temperature region (T<150 K) is attributed to the spin-polarized tunneling at the grain boundaries, while the enhancement at the high temperature region (T>150 K) is primarily due to the inter-rod double exchange.