Magnetoresistance in Heavily Underdoped YBa_2Cu_3O_{6+x}: Antiferromagnetic Correlations and Normal-State Transport

TL;DR

This study investigates the contrasting magnetoresistance behaviors in heavily underdoped YBa_2Cu_3O_{6+x}, revealing the dominant role of antiferromagnetic correlations in out-of-plane transport and minimal impact on in-plane resistivity.

Contribution

It provides new insights into the anisotropic magnetoresistance behavior and the influence of antiferromagnetic correlations in underdoped cuprates.

Findings

Out-of-plane MR increases sharply below T_N.

AF correlations dominate out-of-plane MR behavior.

In-plane resistivity is little affected by AF order.

Abstract

We report on a contrasting behavior of the in-plane and out-of-plane magnetoresistance (MR) in heavily underdoped antiferromagnetic (AF) YBa_2Cu_3O_{6+x} (x<0.37). The out-of-plane MR (I//c) is positive over most of the temperature range and shows a sharp increase, by about two orders of magnitude, upon cooling through the Neel temperature T_N. A contribution associated with the AF correlations is found to dominate the out-of-plane MR behavior for H//c from far above T_N, pointing to the key role of spin fluctuations in the out-of-plane transport. In contrast, the transverse in-plane MR (I//a(b);H//c) appears to be small and smooth through T_N, implying that the development of the AF order has little effect on the in-plane resistivity.