Point Defects in Magnetic Lattices |
Common terms and phrases
antiferromagnetic AS₁ Brillouin function Brillouin zone calculations Callaway Callen chapter classical ground consider contribution correlation function Curie point curves dispersion law dk kČ effect equation of motion exchange integral exp[ik expectation value expression factor ferromagnetic formula given Green-function method Heisenberg Hamiltonian host hw(k ideal crystal ideal lattice integrand interaction k₁ lattice point Lovesey low-temperature region magnetic atoms magnetic impurities MAGNETIC LATTICES magnetic moment magnetic systems magnitude magnon molecular-field model neglected netic netization non-magnetic impurity numerical values obtained onzuiverheid P. A. M. Dirac partial fractions perturbation theory prescription Proc quadratic layer quantity reads H right-hand side second approximation shell spin waves spin-wave variables spingolftheorie sublattice magnetization Substitution summation terms bilinear Uk₂ unperturbed Green functions vanishes wordt yields Yk-k zero zero-point deviation Δμ