Photoinduced magnetism in core/shell prussian blue analogue heterostructures of K_jN_ik[Cr(CN)_6] _l· n H_2O with Rb_aCo_b[Fe(CN) _6]_c· mH_2O

摘要

Core/shell and core/shell/shell particles comprised of the Prussian blue analogues K_jN_ik[Cr(CN)_6]_l· nH_2O (A) and Rb_aCo_b[Fe(CN)_6] _c·mH_2O (B) have been prepared for the purpose of studying persistent photoinduced magnetization in the heterostructures. Synthetic procedures have been refined to allow controlled growth of relatively thick (50-100 nm) consecutive layers of the Prussian blue analogues while minimizing the mixing of materials at the interfaces. Through changes in the order in which the two components are added, particles with AB, ABA, BA, and BAB sequences have been prepared. The two Prussian blue analogues were chosen because B is photoswitchable, and A is ferromagnetic with a relatively high magnetic ordering temperature, ～70 K, although it is not known to exhibit photoinduced changes in its magnetic properties. Magnetization measurements on the heterostructured particles performed prior to irradiation show behavior characteristic of the individual components. On the other hand, after irradiation with visible light, the heterostructures undergo persistent photoinduced changes in magnetization associated with both the B and A analogues. The results suggest that structural changes in the photoactive B component distort the normally photoinactive A component, leading to a change in its magnetization.