Covalent Embedding of Ni2+/Fe3+ Cyanometallate Structures in Silica by Sol–Gel Processing

Abstract

Compound [Ni(AEAPTS)2]3[Fe(CN)6]2 (AEAPTS=N-(2-aminoethyl)-3-aminopropyltrimethoxysilane), in which Ni2+ and Fe3+ ions are ferromagnetically coupled through cyano bridges, was prepared. Sol–gel processing of the AEAPTS derivative resulted in incorporation of the cyanometallate in silica. The obtained material is magnetically ordered below 22 K with an effective magnetic moment μeff of 4.46 μB at room temperature, a maximum of 8.60 μB at approximately 15 K and a narrow hysteresis at 2 K, with a saturation remanence of about 300 emu mol−1 and a coercitivity of 0.03 T.