HIGH-T-C MAGNETS IN A SERIES OF SUBSTITUTED PYRIDINIUM-FEPS3 LAYERED INTERCALATES

A series of sew FePS3 layered intercalation compounds having the gener al formula Fe(1-x)PS(3)G(2x) (where G stands for a monocation) has bee n prepared by cation exchange with several pyridinium derivatives. The occurrence of intralayer Fe2+ vacancies is evidenced by Fe-57 Mossbau er spectroscopy. The magnetic properties of these well-crystallized in tercalates are shown to depend dramatically on the nature of the guest species. Some intercalates remain antiferromagnets as in pristine FeP S3, but those with pyridinium, N-methylpyridinium, and methylviolagen as the guest species acquire a spontaneous magnetization below a criti cal temperature which can be as high as 88 K. The magnetization of the methylviologen intercalate is particularly strong. The magnetization in all cases displays a strong remanance due to single ion anisotropy of the Fe2+ ions and to the Ising character of the magnetic interactio n.