Uniform Mixing of High-Tc Superconductivity and Antiferromagnetism on a Single CuO2 Plane in Hg-based Five-layered Cuprate

TL;DR

This study reveals that in a five-layered Hg-based cuprate, high-temperature superconductivity coexists uniformly with antiferromagnetism on a microscopic level within a single CuO2 plane, challenging previous notions of their mutual exclusivity.

Contribution

First microscopic evidence showing uniform coexistence of high-Tc superconductivity and antiferromagnetism on a single CuO2 plane in a simple cuprate environment.

Findings

Antiferromagnetism appears at 290 K with large magnetic moments on inner planes.

Superconductivity at 72 K coexists with AF order on outer planes.

Coexistence occurs without vortex lattice or stripe order.

Abstract

We report a site selective Cu-NMR study on under-doped Hg-based five-layered high-$T_{\rm c}$ cuprate HgBa2Ca4Cu5Oy with a Tc=72 K. Antiferromagnetism (AF) has been found to take place at TN=290 K, exhibiting a large antiferromagnetic moment of 0.67-0.69uB at three inner planes (IP's). This value is comparable to the values reported for non-doped cuprates, suggesting that the IP may be in a nearly non-doped regime. Most surprisingly, the AF order is also detected with M(OP)=0.1uB even at two outer planes (OP's) that are responsible for the onset of superconductivity (SC). The high-Tc SC at Tc = 72 K can uniformly coexist on a microscopic level with the AF at OP's. This is the first microscopic evidence for the uniform mixed phase of AF and SC on a single CuO2 plane in a simple environment without any vortex lattice and/or stripe order.