Size dependence of the nonlinear transport properties in arrays of nanoconstrictions in phase separated La0.67 Sr0.33 MnO3-δ

Abstract

The transport properties of La0.67 Sr0.33 MnO3-δ nanoconstrictions, with lateral sizes of around 90 nm and 180 nm, respectively, have been studied. Both samples exhibited bias current dependence of resistance and these nonlinear transport properties varied with the size of the nanoconstriction. Compared with the nanoconstriction array of 180 nm, the nanoconstriction array of 90 nm has a lower metal-insulator transition temperature Tp, a larger magnetoresistance at the same bias current, and a larger electroresistance at the same external magnetic field. The experimental features can be understood in the framework of phase separation by taking into account the size dependence of the fraction of insulating phase and the percolation threshold for the metallic phase. The present work sheds some light on the magnetotransport behavior in nanoscaled systems of phase separated manganite. © 2006 The American Physical Society.