Critical dynamics of a nonlocal model and critical behavior of perovskite manganites.
We investigate the nonconserved critical dynamics of a nonlocal model Hamiltonian incorporating screened long-range interactions in the quartic term. Employing dynamic renormalization group analysis at one-loop order, we calculate the dynamic critical exponent z=2+εf_{1}(σ,κ,n)+O(ε^{2}) and the linewidth exponent w=-σ+εf_{2}(σ,κ,n)+O(ε^{2}) in the leading order of ε, where ε=4-d+2σ, with d the space dimension, n the number of components in the order parameter, and σ and κ the parameters coming from the nonlocal interaction term. The resulting values of linewidth exponent w for a wide range of σ is found to be in good agreement with the existing experimental estimates from spin relaxation measurements in perovskite manganite samples.
Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781 039, India.
Rohit
R
Singh
Department of Physics, Handique Girls' College, Guwahati 781 001, India.
Kishore
K
Dutta
Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781 039, India.
Malay K
MK
Nandy