Absence of self-heated bistable resistivity in La₀.₇Sr₀.₃MnO₃ films up to high current densities

Abstract

The E(J) characteristics of well-characterized fully strained epitaxial La₀.₇Sr₀.₃MnO₃ films have been investigated up to high current densities (J10⁴ –10⁵ A/cm²). 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 La₀.₇Sr₀.₃MnO₃ 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 (J5X10⁵ A/cm²).