Evidence for Antiferromagnetic Order in La$_{2-x}$Ce$_{x}$CuO$_{4}$ from Angular Magnetoresistance Measurements

TL;DR

This study uses angular magnetoresistance measurements to reveal antiferromagnetic order in La$_{2-x}$Ce$_{x}$CuO$_{4}$ thin films, showing a twofold symmetry in AMR that diminishes with doping and temperature.

Contribution

It provides evidence of antiferromagnetic order in electron-doped cuprates via AMR, highlighting a twofold symmetry distinct from other cuprates and its temperature dependence.

Findings

Twofold AMR symmetry observed in La$_{2-x}$Ce$_{x}$CuO$_{4}$.

The twofold AMR disappears above a doping-dependent temperature $T_D$.

Antiferromagnetic or spin density wave order likely causes the twofold AMR.

Abstract

We investigated the in-plane angular magnetoresistivity (AMR) of $% T^{^{\prime}}$-phase La$_{2-x}$Ce$_{x}$CuO$_{4}$ (LCCO) thin films ($% x=0.06-0.15$) fabricated by a pulsed laser deposition technique. The in-plane AMR with $\mathbf{H}\parallel ab$ shows a twofold symmetry instead of the fourfold behavior found in other electron-doped cuprates such as Pr$% _{2-x}$Ce$_{x}$CuO$_{4}$ and Nd$_{2-x}$Ce$_{x}$CuO$_{4}$. The twofold AMR disappears above a certain temperature, $T_{D}$. The $T_{D}(x)$ is well above $T_{c}(x)$ for $x=0.06$ ($\sim 110$ K), and decreases with increasing doping, until it is no longer observed above $T_{c}(x)$ at $x=0.15$. This twofold AMR below $T_{D}(x)$ is suggested to originate from an antiferromagnetic or spin density wave order.