THERMOPOWER OF THIN IRON FILMS

Thin iron films were prepared by evaporation in a high vacuum system (pressure in the 10(-5) MPa range). The thermopower was measured in situ near room temperature as a function of film thickness. Iron films with rather high resistivity values showed a strong thickness effect of the Seebeck coefficient, S, with the difference between S (bulk) and S (film) reaching values of up to (19 +/- 3) mu-V/K for a sample 5 nm thick. The difference between S (bulk) and S (film) decreased with increasing d values. However, a sample with a resistance value of 50-mu-OMEGA cm at d = 5 nm had an S value which differed by less than 3-mu-V/K from S (bulk).