Study of exchange and dipolar interaction in MCuX<inf>3</inf>, systems by E.P.R

Compounds of the ABX3type (where A = K, NH4, Cs, Rb, B = Cu, Ni, Cr, X = CI, Br, F, I) make an interesting study by the presence of BX6, B2XA, B3X9, linear chains which also show interesting magnetic properties and crystal structures. Single crystals of KCuCl3, NH4CuCl3, RbCuCl3and CsCuCl3, in the polycrystalline state have been studied by E.P.R. measurements. These compounds show simple E.P.R. spectra but have interesting dependences of line widths on temperature and g values. The line width dependence has been shown to arise from unresolved hyperfine and dipolar interactions, confirmed by second moment calculations. The quasi axial nature of the g value has been explained as being due to antiferro-distortive ordering of the Cu2X26−octahedra. The ammonium ion acts as a better exchange pathway than potassium in the two respective crystals. The E.P.R. intensities have a Curie type dependence and has no contribution from the dimeric coppers. © 1985 Taylor & Francis Group, LLC.