Nuclear spin relaxation and incommensurate magnetism in doped cuprates

TL;DR

This paper investigates nuclear spin relaxation in doped cuprates, linking temperature-independent relaxation to incommensurate magnetic peaks and suggesting a phase transition related to broken electroneutrality, challenging the pseudogap concept.

Contribution

It identifies two distinct relaxation processes in cuprates and proposes a new interpretation involving a phase transition caused by broken electroneutrality.

Findings

Temperature-independent relaxation linked to incommensurate peaks

Universal temperature-dependent relaxation matches 1/{63}^T_{1}(T) in YBCO 124

Proposes a phase transition above T_c due to broken electroneutrality

Abstract

Existing data on Cu-nuclear spin relaxation reveal two independent relaxation processes: the one that is temperature independent we link to incommensurate peaks seen by neutrons, while the ''universal'' temperature dependent contribution coincides with 1/{63}^T_{1}(T) for two-chain YBCO 124. We argue that this new result substitutes for a ''pseudogap'' regime in a broad class of high-T_c cuprates and stems from the 1st order phase transition that starts well above the superconductivity T_c but becomes frustrated because of broken electroneutrality in the CuO_2 plane.