Enhanced low-energy spin dynamics with diffusive character in the iron-based superconductor (La0.87Ca0.13)FePO: Analogy with high Tc cuprates (A short note)

TL;DR

This paper discusses anomalous low-energy spin dynamics in the iron-based superconductor (La0.87Ca0.13)FePO, revealing diffusive behavior similar to high Tc cuprates, based on NMR relaxation measurements.

Contribution

It highlights the diffusive character of spin dynamics in (La0.87Ca0.13)FePO and draws an analogy with high Tc cuprates, providing new insights into superconducting spin behavior.

Findings

NMR relaxation rate 1/T1 depends on measurement frequency.

T dependence of 1/T1 does not decrease as expected in superconducting state.

Similarity between spin dynamics in Fe-based superconductor and high Tc cuprates.

Abstract

In a recent NMR investigation of the iron-based superconductor (La0.87Ca0.13)FePO [Phys. Rev. Lett. 101, 077006 (2008)] Y. Nakai et al. reported an anomalous behavior of the nuclear spin-lattice relaxation of 31P nuclei in the superconducting state: The relaxation rate 1/T1 strongly depends on the measurement frequency and its T dependence does not show the typical decrease expected for the superconducting state. In this short note, we point out that these two observations bear similarity with the situation is some of the high Tc cuprates.