Portal de Periódicos da CAPES

Theory of bloch wall tunnelling

1973; Wiley; Volume: 57; Issue: 1 Linguagem: Inglês

10.1002/pssb.2220570121

1521-3951

T. Egami,

Cold Atom Physics and Bose-Einstein Condensates

Abstract The quantum mechanical tunnelling of a very narrow Bloch wall through the intrinsic barrier is considered. A microscopic theory of the spin wave description of narrow domain walls is developed and subsequently extended to describe the domain wall tunnelling phenomena. The tunnelling probability is presented in two ways, firstly, by the quasi‐particle approach using the conventional W.K.B. approximation and secondly by the method of direct product of state vectors. These two methods are complementary to each other. The results indicate that below the temperature of liquid helium the domain wall diffusion in the rare earth metals and compounds which exhibit high intrinsic coercivity is likely to be governed by the tunnelling process.