Photoenhanced Ferromagnetism in High-K-Containing K-Ni-Cr Prussian Blue Analogues Coated on Rb-Co-Fe Nanocubes.

A large enhancement of the Ni and Cr ferromagnetic moments under UV-light irradiation has been detected in 55 nm thick KNi[Cr(CN)][(HO)]·0.11HO Prussian blue analogues coated on 240 nm RbCo[Fe(CN)][(HO)]·0.56HO nanocubes. Two separate magnetic transitions were found. The one at 72 K marks the magnetic ordering of the Ni and Cr ions on the shell. A higher degree of electronic connection along the Ni-N-C-Cr-C-N-Ni chains was achieved by the incorporation of a larger amount of K ions into the voids enclosed by the NiN and CrC octahedra, which was used to understand the appearance of photoenhanced ferromagnetism in the K-Ni-Cr network. A weak moment developed in the core below 10 K, corresponding to separate ordering of the Co and Fe ions in the Rb-Co-Fe network. Photoinduced ferromagnetism of the Co and Fe ions in the Rb-Co-Fe was also detected.