Domain walls wall energy

Ferromagnetic (In,Mn)As/GaSb heterostructures with rectangular hysteresis show also peculiar light-irradiation effects. In particular, the coercive force is drastically reduced by the illumination, which suggests a reduction of the domain wall pining energy (Oiwa et al. 2001). 

Domain-wall surface energy y, domain-wall width W, single-domain particle diameter Dc, average width of the domain Z) and grain diameter Da in various permanent magnet materials. 

Figure 18.15 Application of the model of hardening-softening transitions to the case of an aged and quenched state of a ferroelectric system with alternating distribution of charged defects, (a) Domain wall free energy versus...

In the finite element solution of the energy equation it is sometimes necessary to impose heat transfer across a section of the domain wall as a boundary condition in the process model. This type of convection (Robins) boundary condition is given as... 

Now since it was shown in Xia and Wolynes [1] that the liquid degrees of freedom below Ta consist of switching to alternative local energy minima, we can claim our assignment of different inelastic modes is exhaustive (but not unique, of course ). These are, again, translations and vibrations of the domain walls. 

We hope to have convinced the reader by now that the tunneling centers in glasses are complicated objects that would have to be described using an enormously big Hilbert space, currently beyond our computational capacity. This multilevel character can be anticipated coming from the low-temperature perspective in Lubchenko and Wolynes [4]. Indeed, if a defect has at least two alternative states between which it can tunnel, this system is at least as complex as a double-well potential—clearly a multilevel system, reducing to a TLS at the lowest temperatures. Deviations from a simple two-level behavior have been seen directly in single-molecule experiments [105]. In order to predict the energies at which this multilevel behavior would be exhibited, we first estimate the domain wall mass. Obviously, the total mass of all the atoms in the droplet... 

Figure 21. A low-energy portion of the energy level structure of a tunneling center is shown. Here e < 0, which means that the reference, liquid, state structure is higher in energy than the alternative configuration available to this local region. A transition to the latter configuration may be accompanied by a distortion of the domain wall, as reflected by the band of higher energy states, denoted as ripplon states.

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