Detailed analysis of the in situ magneto-optic Kerr signal of gadolinium films near the Curie temperature

The temperature and magnetic-field-dependent Kerr signal of layer-by-layer grown 300 Å Gd(0001) on W(110) is analyzed below and above the Curie temperature T_C. The changes in the signal shape when passing through T_C are discussed. We introduce a new and independent method for accurately determining T_C in thin magnetic films in ultrahigh vacuum. As a consequence, discussions of the remanence, the field induced magnetization, and the critical exponent β become more transparent.