Paramagnetic resonance of Cr3+ in the layer structure of NaInS2

The resonance of a localized paramagnetic impurity in a ternary layer structure is reported for the first time. The Cr3+ substitutes for the In3+ and shows a resolved hyperfine interaction with the six coplanar next-neighbor indium cations. An in-plane fractional charge transfer of 3.0% on the indium ions or 1.0% per 3d electron is deduced. g=1.9830.001 and D=-0.03920.003 cm-1 at 300°K. The axial D parameter changes linearly with temperature down to 120°K at a high rate of DT=-0.86 G/°K, which is ascribed to the thermal expansion of the lattice. A comparison between the D parameter observed at 4.2°K and the total uniaxial magnetic anisotropy field of NaCrS2 is made, from which it is concluded that about -17 of the latter quantity results from single-ion ligand field effects. © 1968 The American Physical Society.