Hysteresis in a dipolar Ising model

Zero-temperature Monte Carlo simulations are performed to study the magneti c hysteresis in a three-dimensional model with only dipolar interactions am ong the Ising spins located inside a sphere on a cubic lattice. Relevant di fferences are found in the site energy distributions between the up and dow n spins during the magnetization process. Variations of the dipolar energy and the density of incomplete columns are also discussed. (C) 2000 Elsevier Science B.V. All rights reserved.