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In this work the magnetic Barkhausen noise is studied by two simple 1D models. The first is a spring-block type model which is based on a mechanical analogy and its aim is to explain the basic features of domain-wall dynamics and magnetization processes in ferromagnetic materials. Despite its simplicity the spring-block model yields the realistic shape of hysteresis loops with Barkhausen jumps, it is able to reproduce the interesting phenomenon of disorder-induced phase transition, as well as the good statistics of Barkhausen noise. The second model is a spin Hamiltonian model, which is also a simplified 1D model defined by a Hamiltonian which contains all the interactions that are relevant in real ferromagnets: Ising-type exchange, pinning, interaction with the external field, demagnetization. The model is able to reproduce all the expected statistical properties of Barkhausen noise. In addition, there is a possibility to study the stochastic resonance in this model because it is suitable for Monte Carlo simulations.

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Kovács Katalin obtained PhD degree in 2007 at the Physics Faculty of the Babe -Bolyai University. This work presents two oversimplified one-dimensional models for magnetic Barkhausen-noise that are able to qualitatively reproduce the main features of hysteresis, domain wall dynamics, avalanche-like behavior and all the related scaling properties.

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