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 Seeback coefficient, S, with the difference between S (bulk) and S (film) reaching values of up to (19±3) μV/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 μΩ cm at d = 5 n had an S value which differed by less than 3 μV/K from S (bulk).