In contrast to the experimentally widely used isentropic demagnetization process for cooling to ultra-low temperatures we examine a particular classical model system that does not cool, but rather heats up with isentropic demagnetization. This system consists of several magnetite particles in a colloidal suspension, and shows the uncommon behavior of disordering structurally while ordering magn...

Crystal structure, thermodynamic properties, and adiabatic demagnetization refrigeration (ADR) effect in the spin-$\frac{7}{2}$ triangular antiferromagnet $\mathrm{KBaGd}{({\mathrm{BO}}_{3})}_{2}$ are reported. With average nearest-neighbor exchange coupling of 44 mK, this compound shows magnetic order below ${T}_{N}=263$ mK zero field. The ADR tests reach temperature ${T}_{min}=122\phantom{\ru...

Demagnetization, commonly employed to study ferromagnets, has been proposed as the basis for an optimization tool, a method to find the ground state of a disordered system. Here we present a detailed comparison between the ground state and the demagnetized state in the random field Ising model, combing exact results in d = 1 and numerical solutions in d = 3. We show that there are important dif...

The superconductivity at 39 K discovered in MgB2 among simple binary chemical composition attracted much interest in its fabrication techniques and practical applications [1]. MgB2 superconductor exhibits many impressive properties such as highest critical temperature amongst intermetallic superconductors which means low cooling costs, impressive grain boundary transparency to the flow of curre...

This paper presents the design process of a high performance 3-phase 3.7 kW 2-pole line start permanent magnet synchronous motor for pumping system. A method was proposed to study the starting torque characteristics considering line start with high inertia load. A d-q model including cage was built to study the synchronization capability. Time-stepping finite element method analysis was utilize...

At the Advanced Photon Source (APS) concern for radiation-induced demagnetization of the insertion devices (IDs) in the storage ring and in the free-electron laser has initiated systematic radiation effects studies towards the development of efficient techniques for ID protection. The studies include radiation dose monitoring, parametric study of the radiation-induced demagnetization, as well a...

We have studied the magnetization dynamics of disk array La0.7Sr0.3MnO3 ferromagnetic by means of timeresolved micromagnetic simulation. The coercivity field (Hc) is assumed depend on the interdisk distance. Meanwhile, the distribution of C-states of disk array, in the along of the same diagonal, exhibits an opposite state which is called positive Cstates and negative C-states. Along of the sam...

We analyze low field hysteresis close to the demagnetized state in disordered ferromagnets using the zero temperature random-field Ising model. We solve the demagnetization process exactly in one dimension and derive the Rayleigh law of hysteresis. The initial susceptibility a and the hysteretic coefficient b display a peak as a function of the disorder width. This behavior is confirmed by nume...

We studied the electronic and magnetic dynamics of ferromagnetic insulating BaFeO_{3} thin films by using pump-probe time-resolved resonant x-ray reflectivity at the Fe 2p edge. By changing the excitation density, we found two distinctly different types of demagnetization with a clear threshold behavior. We assigned the demagnetization change from slow (∼150  ps) to fast (<70  ps) to a transiti...