1207.2623 (Elisabeth S. Knowles et al.)

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

Elisabeth S. Knowles, Matthieu F. Dumont, Marcus K. Peprah, Mark W. Meisel, Carissa H. Li, Matthew J. Andrus, Daniel R. Talham

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.

View original: http://arxiv.org/abs/1207.2623