Self-organized criticality in the hysteresis of the Sherrington-Kirkpatrick model

We study hysteretic phenomena in random ferromagnets. We argue that the angle dependent magnetostatic (dipolar) terms introduce frustration and long-range interactions in these systems. This makes it plausible that the Sherrington-Kirkpatrick (SK) model may be able to capture some of the relevant physics of these systems. We use scaling arguments, replica calculations, and large scale numerical simulations to characterize the hysteresis of the zero temperature SK model. By constructing the distribution functions of the avalanche sizes, magnetization jumps, and local fields, we conclude that the system exhibits self-organized criticality everywhere on the hysteresis loop.