Magnetoresistance and spin fluctuation resistivity of α-Mn thin films and their relationship to substrate temperatures

Abstract

Electrical resistivity measurements in thermally evaporated α-Mn thin films have been carried out between 10 and 1.4 K using the van der Pauw four probe technique in magnetic fields up to 9 T. The results reveal a wide variation of the anomalous coefficient of T2 at low temperatures. This variation is found to be influenced by substrate temperatures. At high substrate temperatures (approximately 300 °C) a film whose residual resistivity in the expected range (0.10-0.85 μΩm) of bulk α-Mn is formed and its anomalously large coefficient of T2 at low temperatures is found to decrease appreciably with magnetic field. The magnitude of the resistivity at such low temperatures does not change for films coated on substrates held below 200 °C in fields up to 9 T. In such films the coefficient of T2 is negative and the magnitude of the coefficient of T2, (A) increases with decreasing substrate temperatures.