Spinglass freezing in Kondolattice compounds
Abstract
A theory is presented that describes a spinglass phase at finite temperatures in Kondolattice systems with an additional RudermanKittelKasuyaYosida interaction represented by long range, random couplings among localized spins as in the SherringtonKirkpatrick (SK) spinglass model. The problem is studied within the functional integral formalism where the spin operators are represented by bilinear combinations of fermionic (anticommuting) Grassmann variables. The Kondo and spinglass transitions are both described with the meanfieldlike static ansatz that reproduces good results in the two wellknown limits. At high temperatures and low values of the Kondo coupling there is a paramagnetic (disordered) phase with vanishing Kondo and spinglass order parameters. By lowering the temperature, a second order transition line is found at T_{SG} to a spinglass phase. For larger values of the Kondo coupling there is a second order transition line at roughly T_{k} to a Kondo ordered state. For T<T_{SG} the transition between the Kondo and spinglass phases becomes first order.
 Publication:

Physical Review B
 Pub Date:
 February 2001
 DOI:
 10.1103/PhysRevB.63.054409
 arXiv:
 arXiv:condmat/0009197
 Bibcode:
 2001PhRvB..63e4409T
 Keywords:

 75.10.Nr;
 05.50.+q;
 64.60.Cn;
 Spinglass and other random models;
 Lattice theory and statistics;
 Orderdisorder transformations;
 statistical mechanics of model systems;
 Condensed Matter  Statistical Mechanics;
 Condensed Matter  Disordered Systems and Neural Networks
 EPrint:
 21 pages, 1 figure, to appear on Phys. Rev. B