Spin-lattice relaxation within a dimerized Ising chain in a magnetic field
- Department of Physics, Akdeniz University, 07058 Antalya (Turkey)
- Department of Physics, Dokuz Eylül University, 35160 İzmir (Turkey)
- Department of Physics, Niğde University, 51240 Niğde (Turkey)
- Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61–614 Poznań (Poland)
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 obtained 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.
- OSTI ID:
- 22308505
- Journal Information:
- Journal of Applied Physics, Vol. 116, Issue 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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