Point-contact spectroscopy for itinerant-magnetic material of Fe x TiS2

The nonlinear current-voltage characteristics of a homojunction point contact of 1T-CdI₂-type layered crystal TiS₂ and its intercalation compound of itinerantmagnetic Fe _x TiS₂ have been measured at 1.4 K. For the magnetic samples, both a maximum and a minimum in thedI/dV-V curves are observed within a restricted range of the initial differential resistancesR _d(0). Electron-magnon scatterings are responsible for the appearance of the minimum at a bias voltageV _B(min), which depends onR _d(0). These results are discussed using the conventional spherical spreading out model, together with a heating model. The agreement between experiment and theory is apparently good if a large background is taken into account, but with unusually large andR _d(0)-dependent Lorenz number.