Magnetoresistive study of antiferromagnetic--weak ferromagnetic transition in single-crystal La$_{2}$CuO$_{4+\delta}$

TL;DR

This study investigates how magnetic fields induce an antiferromagnetic to weak ferromagnetic transition in La$_2$CuO$_4$ single crystals, significantly affecting their electrical resistance and supporting a 3D hopping conduction model.

Contribution

First to demonstrate the impact of the AF-WF transition on conductivity in La$_2$CuO$_4$ single crystals along the CuO$_2$ layers.

Findings

Resistance drops sharply at 5-7 T during the transition.

The AF-WF transition influences conductivity in the layered oxide.

Results support 3D hopping conduction in La$_2$CuO$_4$.

Abstract

The resistive measurements were made to study the magnetic field-induced antiferromagnetic (AF) - weak ferromagnetic (WF) transition in La$_2$CuO$_4$ single-crystal. The magnetic field (DC or pulsed) was applied normally to the CuO$_2$ layers. The transition manifested itself in a drastic decrease of the resistance in critical fields of ~5-7 T. The study is the first to display the effect of the AF -WF transition on the conductivity of the La$_2$CuO$_4$ single-crystal in the parallel - to - CuO$_2$ layers direction. The results provide support for the 3-dimensional nature of the hopping conduction of this layered oxide.