Crystal fields and magnetic interactions in TmT2Si2 (T = Co, Ni, Cu)

An inelastic neutron scattering and 166Er Mossbauer spectroscopy study was performed on ErCo2Si2 and a 169Tm Mossbauer spectroscopy study was performed on TmT2Si2 (T = Co and Ni). The saturation Er moment in ErCo2Si2 was found to be 7.8 µB and the saturation Tm moment in TmCo2Si2 was determined to be 6.5 µB. A crystal field interpretation of ErCo2Si2 and TmT2Si2 (T = Co and Ni) is presented and, together with a new interpretation for existing data for T = Cu, trends in the crystal field parameters within the TmT2Si2 series are presented.