Absence of self-heated bistable resistivity inLa0.7Sr0.3MnO3films up to high current densities

Abstract

The $E(J)$ characteristics of well-characterized fully strained epitaxial ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_{3}$ films have been investigated up to high current densities $(J\ensuremath{\sim}{10}^{4}--{10}^{5}\text{ }\text{A}/{\text{cm}}^{2})$. Different electric contact resistances and different current path configurations have been used to sort out the role of Joule self-heating from contact heating in the transport properties. It is demonstrated through macroscopic transport and conductive scanning force microscopy measurements that contact heating may lead to nonlinear and irreversible $E(J)$ characteristics when high contact resistances are used. Low dissipative contact power measurements are crucial to define the upper $J$ limits to keep linear and reversible $E(J)$ characteristics. We demonstrate that Joule self-heating in ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_{3}$ thin films only induces moderate warming at high temperatures while achieving bistable resistivity at low temperatures would require the use of very high current densities $(J\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{5}\text{ }\text{A}/{\text{cm}}^{2})$.