Muon spin relaxation study of the magnetism in unilluminated Prussian Blue analogue photomagnets

TL;DR

This study uses muon spin relaxation to investigate the magnetic properties of unilluminated Prussian blue analogue photomagnets, revealing a correlation between magnetic ordering and composition explained by a site percolation model.

Contribution

It provides new insights into the magnetic behavior of unilluminated Prussian blue analogues and introduces a site percolation model to explain the observed correlations.

Findings

Magnetic ordering varies with composition parameter x.

Evidence supports a site percolation model for magnetic correlations.

Unilluminated state shows distinct magnetic properties compared to photo-sensitive states.

Abstract

We present longitudinal field muon spin relaxation ($\mu$SR) measurements in the unilluminated state of the photo-sensitive molecular magnetic Co-Fe Prussian blue analogues M$_{1-2x}$Co$_{1+x}$[Fe(CN)$_6$]$\cdot z$ H$_2$O, where M=K and Rb with $x=0.4$ and $\simeq 0.17$, respectively. These results are compared to those obtained in the $x=0.5$ stoichiometric limit, Co$_{1.5}$[Fe(CN)$_6$]$\cdot 6$ H$_2$O, which is not photo-sensitive. We find evidence for correlation between the range of magnetic ordering and the value of $x$ in the unilluminated state which can be explained using a site percolation model.