Observation of Colossal Terahertz Magnetoresistance and Magnetocapacitance in a Perovskite Manganite

TL;DR

This study reports large, non-saturating terahertz magnetoresistance and magnetocapacitance in La$_{0.875}$Sr$_{0.125}$MnO$_3$, highlighting its potential for magnetic terahertz device applications.

Contribution

It provides the first detailed observation of colossal terahertz magnetoresistance and magnetocapacitance in a perovskite manganite at the Curie temperature.

Findings

60% increase in terahertz resistance at 180 K and 6 T

15% increase in terahertz capacitance at 180 K and 6 T

Effects explained by a two-phase coexistence model

Abstract

We have studied the terahertz response of a bulk single crystal of La$_{0.875}$Sr$_{0.125}$MnO$_3$ at around its Curie temperature, observing large changes in the real and imaginary parts of the optical conductivity as a function of magnetic field. The terahertz resistance and capacitance extracted from the optical conductivity rapidly increased with increasing magnetic field and did not show any sign of saturation up to 6 T, reaching 60% and 15%, respectively, at 180 K. The observed terahertz colossal magnetoresistance and magnetocapacitance effects can be qualitatively explained by using a two-component model that assumes the coexistence of two phases with vastly different conductivities. These results demonstrate the potential use of perovskite manganites for developing efficient terahertz devices based on magnetic modulations of the amplitude and phase of terahertz waves.