skip to main content

Title: Spin-lattice relaxation within a dimerized Ising chain in a magnetic field

A qualitative study of the spin-lattice relaxation within a dimerized Ising chain in a magnetic field is presented. We have first determined the time dependence of the deviation of the lattice distortion parameter δΔ from the equilibrium state within framework of a technique combining the statistical equilibrium theory based on the transfer matrix method and the linear theory of irreversible thermodynamics. We have shown that the time dependence of the lattice distortion parameter is characterized by a single time constant (τ) which diverges around the critical point in both dimerized (Δ≠0) and uniform (Δ=0) phase regions. When the temperature and magnetic field are fixed to certain values, the time τ depends only on exchange coupling between the spins. It is a characteristic time associated with the long wavelength fluctuations of distortion. We have also taken into account the effects of spatial fluctuations on the relaxation time using the full Landau-Ginzburg free energy functional. We have found an explicit expression for the relaxation time as a function of temperature, coupling constant and wave vector (q) and shown that the critical mode corresponds to the case q=0. Finally, our results are found to be in good qualitative agreement with the results obtainedmore » in recent experimental study on synchrotron x-ray scattering and muon spin relaxation in diluted material Cu{sub 1−y}Mg{sub y}GeO{sub 3} where the composition y is very close to 0.0209. These results can be considered as natural extensions of some previous works on static aspects of the problem.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Department of Physics, Akdeniz University, 07058 Antalya (Turkey)
  2. Department of Physics, Dokuz Eylül University, 35160 İzmir (Turkey)
  3. Department of Physics, Niğde University, 51240 Niğde (Turkey)
  4. Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61–614 Poznań (Poland)
Publication Date:
OSTI Identifier:
22308505
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COUPLING CONSTANTS; EQUILIBRIUM; FLUCTUATIONS; FREE ENERGY; ISING MODEL; MAGNETIC FIELDS; MUON SPIN RELAXATION; RELAXATION TIME; SPIN; SPIN-LATTICE RELAXATION; SYNCHROTRON RADIATION; TEMPERATURE DEPENDENCE; THERMODYNAMICS; TIME DEPENDENCE; TRANSFER MATRIX METHOD; WAVELENGTHS; X-RAY DIFFRACTION