Magnetization reversal dynamics in mesoscopic Ni80Fe20 dots

Abstract

The magnetization reversal dynamics in permalloy dots (20 similar to 400 mum diameter) has been investigated as a function of the applied field amplitude H-0 and frequency Omega using scanning Kerr microscopy. An increase in the dynamic coercivity with reduced size is observed for d < 100 mum in the frequency range up to 800 Hz. The loop area A follows the scaling relation A proportional to H(0)(alpha)Omega (beta), with alpha approximate to 0.14 and beta approximate to 0.50 throughout the entire size range studied. These results demonstrate that the dynamic scaling behavior is universal even though the lateral size influences the domain structure and magnetic reversal behavior.