Size Effects of Switching Fields of Thin Permalloy Particles

Measurements of hysteresis loops were performed on thin permalloy rectangular platelets with various dimensions prepared by nanolithography. The particle coerclvlty, Hc, exhibits a sensitive size dependence. The measured Hc are compared with micromagnetic predictions utilizing two-dimensional models without magnetization variation through the thickness. Excellent overall agreement is found, indicating that a simplified two-dimensional approach is sufficient for characterizing reversal mechanisms for particles with thicknesses smaller than or comparable to the exchange length. © 1992 IEEE