Ground state optimization and hysteretic demagnetization: the random-field Ising model

Details Ground state optimization and hysteretic demagnetization: the random-field Ising model Ground state optimization and hysteretic demagnetization: the random-field Ising model

2004-07-12

arxiv.org/abs/cond-mat/0407297v1

Physics

Condensed Matter

Statistical Mechanics

13 figs. Submitted to Phys. Rev. B

Scientific paper

10.1103/PhysRevB.71.064423

We compare the ground state of the random-field Ising model with Gaussian distributed random fields, with its non-equilibrium hysteretic counterpart, the demagnetized state. This is a low energy state obtained by a sequence of slow magnetic field oscillations with decreasing amplitude. The main concern is how optimized the demagnetized state is with respect to the best-possible ground state. Exact results for the energy in d=1 show that in a paramagnet, with finite spin-spin correlations, there is a significant difference in the energies if the disorder is not so strong that the states are trivially almost alike. We use numerical simulations to better characterize the difference between the ground state and the demagnetized state. For d>=3 the random-field Ising model displays a disorder induced phase transition between a paramagnetic and a ferromagnetic state. The locations of the critical points R_c(DS), R_c(GS) differ for the demagnetized state and ground state. Consequently, it is in this regime that the optimization of the demagnetized stat is the worst whereas both deep in the paramagnetic regime and in the ferromagnetic one the states resemble each other to a great extent. We argue based on the numerics that in d=3 the scaling at the transition is the same in the demagnetized and ground states. This claim is corroborated by the exact solution of the model on the Bethe lattice, where the R_c's are also different.

Affiliated with

Also associated with

No associations

Rating

Ground state optimization and hysteretic demagnetization: the random-field Ising model does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Ground state optimization and hysteretic demagnetization: the random-field Ising model, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ground state optimization and hysteretic demagnetization: the random-field Ising model will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-58133