Abstract
The magnetic structures and hysteresis loops of permalloy thin film arrays are investigated here using magnetic force microscopy and vibrating sample magnetometer. The strength of interparticle dipole interaction can be revealed by the number of single-domain pairs with antiparallel magnetizations when the array is relaxed from a strong hard-axis field. Besides, hysteresis loops obtained by vibrating sample magnetometer measurements show that arrays with narrower interparticle spacings have lower coercivities and remanences. The results obtained from vibrating sample magnetometer are in very good agreement with magnetic force microscopy imaging. © 2005 American Institute of Physics.