Barkhausen Noise and Critical Scaling in the Demagnetization Curve

TL;DR

This study investigates the critical behavior of the demagnetization curve through Barkhausen noise analysis using a non-equilibrium Ising model, revealing critical scaling and exponents related to disorder and long-range fields.

Contribution

It demonstrates the critical scaling properties of the demagnetization curve and derives related critical exponents from the saturation loop and subloops.

Findings

Critical scaling observed for avalanche sizes and spanning avalanches.

Critical exponents related to the saturation loop and subloops are derived.

Behavior in the presence of long-range demagnetizing fields is discussed.

Abstract

The demagnetization curve, or initial magnetization curve, is studied by examining the embedded Barkhausen noise using the non-equilibrium, zero temperature random-field Ising model. The demagnetization curve is found to reflect the critical point seen as the system's disorder is changed. Critical scaling is found for avalanche sizes and the size and number of spanning avalanches. The critical exponents are derived from those related to the saturation loop and subloops. Finally, the behavior in the presence of long range demagnetizing fields is discussed. Results are presented for simulations of up to one million spins.