Scaling of hysteresis and transition parameter with grain size in longitudinal thin film media

Scaling relations of hysteresis loops and single transitions with respect to grain size were obtained by numerical simulation of closely packed 64×64 uniform hexagonal grains. The smallest obtainable transition parameter was found to be half the grain size (D). An approximate formula to relate the simulation data with the Williams-Comstock model was found to be $\mathrm{a/D\approx }\sqrt{{\text{0.5}}^2{\text{+0.35(a}}_{\mathrm{WC}}{\mathrm{/D)}}^2}$ valid only for $\text{t/D⩽2.0,}$ $\text{d+t/2⩽3.5D}$ and $M_s{\mathrm{/H}}_k\text{⩽0.1.}$