Photoinduced Perturbations of the Magnetic Superexchange in Core-Shell Prussian Blue Analogues

TL;DR

This study investigates how light exposure affects magnetic interactions in core-shell Prussian blue analogues, revealing strain-induced changes in superexchange interactions and magnetization behavior.

Contribution

It demonstrates that photoinduced lattice expansion in the B layer causes strain that perturbs superexchange interactions in the A layer of core-shell Prussian blue analogues.

Findings

Photoinduced decrease in magnetization below Tc of A layer.

Strain from B layer affects superexchange J in A layer.

Persistent photoinduced effects similar to pressure-induced changes.

Abstract

Cubic heterostructured (BA) particles of Prussian blue analogues, composed of a shell of ferromagnetic K_{0.3}Ni[Cr(CN)_6]_{0.8} \cdot 1.3H_2O (A), Tc ~ 70 K, surrounding a bulk core of photoactive ferrimagnetic Rb_{0.4}Co[Fe(CN)_6]_{0.8} \cdot 1.2H_2O (B), Tc ~20 K, have been studied. Below Tc ~ 70 K, these samples exhibit a persistent photoinduced decrease in low-field magnetization, and these results resemble data from other core-shell particles and analogous ABA heterostructured films. This net decrease suggests that the photoinduced lattice expansion in the B layer generates a strain-induced decrease in the magnetization of the A layer, similar to a pressure-induced decrease observed by others in a pure A-like material and by us in our BA cubes. Upon further examination, the data also reveal a significant portion of the A material whose superexchange, J, is perturbed by the photoinduced strain from the B constituent.