The Spin Transition of an Iron(III) Complex Intercalated in a MnPS3Layered Magnet. Occurrence of a Hysteresis Effect on Removal of Lattice Solvent

Abstract

A cationic iron(III) complex [FeIII(5-OMe-sal2trien]+ (where [H2(5-OMe-sal)2trien] was derived from triethylenetetramine and substituted salicylaldehyde), designed to undergo spin crossover, has been inserted in the layered MnPS3 host lattice. The magnetic properties of the resulting intercalation compound [Fe(5-OMe-sal2trien)]0.28Mn0.86PS3·nH2O have been characterized by 57Fe Mossbauer spectrometry and SQUID measurements. The untreated compound exhibits a sluggish thermal spin crossover over the range 200−300 K, but without hysteresis. Removing the co-intercalated water molecules from the compound dramatically affects its behavior and confers a broad hysteresis loop to the transition. The appearance of cooperativity is discussed in terms of elastic interactions and specific arrangement of the ferric complexes. Further interest arises from the spontaneous magnetization acquired by the intercalation compound below 36 K. The static internal magnetic field experienced by the iron sites affects the Mossbauer ...