"Spin-Flop" Transition and Anisotropic Magnetoresistance in Pr_{1.3-x}La_{0.7}Ce_{x}CuO_{4}: Unexpectedly Strong Spin-Charge Coupling in Electron-Doped Cuprates

TL;DR

This study reveals a strong spin-charge coupling in electron-doped cuprates, demonstrated by a magnetic-field-induced spin transition that significantly alters resistivity and exhibits complex angular magnetoresistance behavior.

Contribution

It uncovers a novel spin-flop transition in Pr_{1.3-x}La_{0.7}Ce_{x}CuO_{4} and its profound impact on magnetoresistance, highlighting unexpected spin-charge interactions.

Findings

Magnetic-field induces a transition from noncollinear to collinear spin arrangement.

Magnetoresistance exhibits a four-fold symmetric angular dependence.

Magnetoresistance exceeds 30% at low temperatures, indicating strong spin-charge coupling.

Abstract

We use transport and neutron-scattering measurements to show that a magnetic-field-induced transition from noncollinear to collinear spin arrangement in adjacent CuO_{2} planes of lightly electron-doped Pr_{1.3-x}La_{0.7}Ce_{x}CuO_{4} (x=0.01) crystals affects significantly both the in-plane and out-of-plane resistivity. In the high-field collinear state, the magnetoresistance (MR) does not saturate, but exhibits an intriguing four-fold-symmetric angular dependence, oscillating from being positive at B//[100] to being negative at B//[110]. The observed MR of more than 30% at low temperatures induced by a modest modification of the spin structure indicates an unexpectedly strong spin-charge coupling in electron-doped cuprates.