Field sweep rate dependence of media dynamic coercivity

The dependence of the media dynamic coercivity dependence on field sweeping rate was obtained for a general case with the media energy barrier ΔE=K_uV(1-H/H₀)ⁿ. The effective coercivity measurement time t_eff for a linearly sweeping field is derived. The general solution was applied to perpendicular media (n=2). The difference in perpendicular media coercivity with a step field and linearly sweeping field is calculated for various H₀ and K_uV/(k_BT). The dynamic coercivity of perpendicular media samples was measured using a Kerr-effect magnetometer with both field sweep rate and finite time duration schemes. The calculated coercivity is compared to measurement results.