Abstract
The critical phase transition in ferromagnetic ultrathin Fe/W(110) films has been studied using the magnetic ac susceptibility. A statistically objective, unconstrained fitting of the susceptibility is used to extract values for the critical exponent the critical temperature the critical amplitude and the range of temperature that exhibits power-law behavior from individual experimental measurements of This avoids systematic errors and generates objective fitting results. An ensemble of 25 measurements on many different films are analyzed. Those which permit a fitting range in reduced temperature extending lower than give an average value Bilayer films give a weighted average value of These results are in agreement with the two-dimensional Ising exponent Measurements that do not exhibit power-law scaling as close to (especially films of thickness 1.75 monolayer) show a value of higher than the Ising value. Several possibilities are considered to account for this behavior.
- Received 29 July 2003
DOI:https://doi.org/10.1103/PhysRevB.69.094411
©2004 American Physical Society