Magnetic hysteresis and Barkhausen noise in thin Fe films at 10 K

The role of temperature during magnetization reversal in a thin Fe film grown on MgO has been investigated. At a microscopic level the process takes place through jumps whose amplitude ΔM follows a power-law probability distribution: P(ΔM) = ΔM−α, with α = 1 at 300 K and 1.8 at 10 K. During each avalanche, thermal activation does not play a relevant role in the initial overcoming of the potential barrier and therefore the temperature-dependent amplitude probability is related to cooperative effects taking place during the avalanche itself.