Magnetic hysteresis dynamics: Thin p(1x1) Fe films on flat and stepped W(110)

Hysteresis properties of ultrathin (1.5-4 monolayer) epitaxial Ee films grown on flat and stepped W(110) surfaces are studied as a function of film thickness, temperature, and the strength and frequency of the applied sinusoidal magnetic field. Power law scaling of the hysteresis loop area is observed over five decades in frequency. Measured exponents depart significantly from those reported based on prior experiments and existing theoretical models. An abrupt transition from switching behavior to a Stable magnetic state is observed at a critical frequency where the dynamic coercivity exceeds the applied field strength.