Improvement of Electromagnetic Wave Absorption Ability by Reducing Impedance Oscillation Characteristics

Abstract

Analytic expressions are derived in the high temperature limit for the low-order frequency moments (up to the fourth) of the spin correlation function for a dilute Heisenberg paramagnet having both uniaxial anisotropic exchange and single-ion uniaxial anisotropy. Both the longitudinal and transverse moments are considered and general results for arbitrary spin and arbitrary range of the magnetic interactions are presented. The results are specialised to a number of simple lattices (linear, square, simple cubic, body-centred cubic and face-centred cubic) having nearest-neighbour and second nearest-neighbour interactions only.