A magnetic analog of the isotope effect in cuprates

TL;DR

This study investigates the magnetic properties of different cuprate families, revealing a universal relation between superconducting transition temperature, magnetic exchange, and carrier density, akin to the isotope effect.

Contribution

It introduces a universal magnetic relation in cuprates linking Tc, magnetic exchange, and carrier density across multiple families with minimal structural variation.

Findings

Universal Tc=c*J*n_s relation observed across all families

Magnetic measurements show consistent in-plane exchange interactions

Minimal structural changes across different cuprate families

Abstract

We present extensive magnetic measurements of the (Ca_xLa_{1-x})(Ba_{1.75-x}La_{0.25+x})Cu_{3}O_{y} (CLBLCO) system with its four different families (x) having a Tc^max(x) variation of 28% and minimal structural changes. For each family we measured the Neel temperature, the anisotropies of the magnetic interactions, and the spin glass temperature. Our results exhibit a universal relation Tc=c*J*n_s for all families, where c~1, J is the in plane Heisenberg exchange, and n_s is the carrier density. This relates cuprate superconductivity to magnetism in the same sense that phonon mediated superconductivity is related to atomic mass.