Studies on the linear chain antiferromagnets: Ba₂MnX₃ (X = S, Se, Te) and Their Solid Solutions

The linear chain antiferromagnetism previously reported for Ba₂MnS₃ and Ba₂MnSe₃ is now demonstrated for Ba₂MnTe₃. The mixed-chalcogenide solid solutions Ba₂MnX_xX^′_3-x (X, X′ = S, Se, Te; x = 0, 1, 2) have been prepared and their electrical and magnetic properties studied. All of the phases are insulating with room temperature resistivities of approximately 10²-10³ Ω cm. The magnetic susceptibility curves of these mixed-chalcogenide phases exhibit broad maxima typical of one dimensional magnetic ordering. The linear-chain model of Bonner-Fisher for Heisenberg-type ions was applied to the susceptibility data. The geometry of the superexchange pathway appears to be critical in determining the strength of the magnetic coupling, with the polarizability of the bridging atom having little effect.