THE EFFECT OF SUBSTRATE TEMPERATURES ON THE HALL-COEFFICIENT OF ALPHA-MN THIN-FILMS

Hall coefficient measurements in evaporated alpha-Mn thin films have b een carried out in magnetic fields up to 63 kG in the temperature rang e between 1.5 and 100 K using the van der Pauw four probe technique. T he results show a range of temperature variation of the Hall coefficie nt (R-H) depending upon the substrate temperatures used. At high subst rate temperatures (T-s > 100 degrees C) and in high vacuum the sign of R-H changes from negative to positive as the temperature is lowered f rom 100 to 1.5 K, whilst at low substrate temperatures (T-s 30 degrees C) and in a similar vacuum the sign of R-H remains negative. The resu lts of the Hall coefficient in the films are analysed using the two ba nd model of conduction with temperature independent carrier concentrat ions, (C) 1997 Elsevier Science S.A.