Magnetic order in quasi-two-dimensional molecular magnets investigated with muon-spin relaxation

TL;DR

This study uses muon-spin relaxation to investigate magnetic ordering in layered quasi-2D molecular antiferromagnets, revealing ordering temperatures, critical behavior, and inter-layer interactions that are difficult to detect with traditional methods.

Contribution

It provides new insights into magnetic ordering in quasi-2D molecular magnets using muSR, including identification of ordering temperatures and analysis of inter-layer coupling.

Findings

Detection of magnetic ordering temperatures in layered molecular magnets.

Estimation of inter-layer exchange coupling and in-layer correlation lengths.

Identification of muon stopping sites and magnetic structure analysis.

Abstract

We present the results of a muon-spin relaxation (muSR) investigation into magnetic ordering in several families of layered quasi-two-dimensional molecular antiferromagnets based on transition metal ions such as S=1/2 Cu2+ bridged with organic ligands such as pyrazine. In many of these materials magnetic ordering is difficult to detect with conventional magnetic probes. In contrast, muSR allows us to identify ordering temperatures and study the critical behavior close to T_N . Combining this with measurements of in-plane magnetic exchange J and predictions from quantum Monte Carlo simulations we may assess the degree of isolation of the 2D layers through estimates of the effective inter-layer exchange coupling and in-layer correlation lengths at T_N . We also identify the likely metal-ion moment sizes and muon stopping sites in these materials, based on probabilistic analysis of the magnetic structures and of muon-fluorine dipole-dipole coupling in fluorinated materials.