Current oscillation and low-field colossal magnetoresistance effect in phase-separated manganites

TL;DR

This paper reports on current-induced switching and low-field colossal magnetoresistance in phase-separated manganites, revealing oscillations in current due to local switching of conduction paths, with potential implications for electronic devices.

Contribution

It demonstrates current oscillations and magnetoresistance effects in phase-separated manganites, modeled by local switching of conduction paths, advancing understanding of their electronic properties.

Findings

Current-induced switching from metallic to insulating states.

Low-field negative magnetoresistance effect observed.

Current oscillations occur above a threshold voltage.

Abstract

Current-induced switching from metallic to insulating state is observed in phase-separated states of (La_{1-y}Pr_y)_{0.7}Ca_{0.3}MnO_3 (y=0.7) and Nd_{0.5}Ca_{0.5}Mn_{1-z}Cr_zO_3 (z=0.03) crystals. Application of magnetic fields to this current-induced insulating state causes pronounced low-field negative magnetoresistance effect [r(H)/r(0)=10^{-3} at H=1kOe]. Application of a constant voltage also causes breakdown of ohmic relation above a threshold voltage. At voltages higher than this threshold value, oscillations in currents are observed. This oscillation is well reproduced by a simple model of local switching of a percolative conduction path.