Two different types of nonlinear current-voltage characteristics are observed in oxygen-deficient La0.67 Ca0.33 MnO3-y (LCMO) films at temperatures below the insulator-metal transition. The paraboliclike dynamic conductance G (V), defined as dI / dV, curves near the zero bias observed in highly oxygen-deficient LCMO films implies the contribution from the spin-dependent tunneling transport between ferromagnetic clusters, with magnetic-disordered regions serving as tunneling barriers. On the other hand, for the slightly oxygen-deficient LCMO films, dips around the zero bias were observed in nonlinear G (V) curves and have been attributed to spin-flip scattering, with oxygen vacancies serving as scattering centers.
|Journal||Journal of Applied Physics|
|State||Published - 7 Feb 2008|