Mössbauer Relaxation Studies of π-Domain-Wall Dynamics in Pure and Impure Ising-Type Magnetic Chains

  • H. J. M. de Groot
  • R. C. Thiel
  • L. J. de Jongh
Conference paper
Part of the Springer Series in Solid-State Sciences book series (SSSOL, volume 54)

Abstract

The subject of domain-wall dynamics in Ising-type ferro- and antiferromagnetic chains has recently become of great interest, since they provide a simple and readily accessible possibility to study nonlinear excitations [1,2]. By Ising-type is meant that there is a preferential direction for the moments, either through crystal field effects or dipolar anisotropy. Consequently, π-domain-walls can be present even in zero magnetic field and their density will determine the intrachain correlation length at low temperatures. In experimental quasi one-dimensional (1-d) magnetic systems, such walls are thermally excited because of entropy considerations. In the paramagnetic regime T>Tc, where Tc is the transition temperature to 3-d long-range order (due to the weak interchain coupling), the walls may propagate more or less freely along each of the chains. However, as Tc is approached more closely (e.g. within 10%), the interchain coupling provides a progressive damping mechanism for the wall-motion, and finally below Tc the walls become blocked and form a static 3-d domain structure. Thus, in a certain range above Tc the density of walls and their motion effectively determine the spin correlation function \( \left\langle {\vec s(0,0)\vec s(z,t)} \right\rangle \) , which may be studied by neutron scattering and such microscopic probes as NMR and Mössbauer effect experiments [1,2]. In the present work we briefly review a number of Mössbauer studies recently performed at our laboratory, as well as the relevant theoretical descriptions.

Keywords

Entropy Anisotropy Agate Soliton Sine 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1984

Authors and Affiliations

  • H. J. M. de Groot
    • 1
  • R. C. Thiel
    • 1
  • L. J. de Jongh
    • 1
  1. 1.Kamerlingh Onnes Laboratorium der Rijksuniversiteit te LeidenLeidenThe Netherlands

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