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Collective Excitations of Localized Electrons and Their Effect on Magnetic‐Material Kinetics
Author(s) -
Mitsek A. I.
Publication year - 1989
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221560214
Subject(s) - condensed matter physics , antiferromagnetism , electron , excitation , pairing , hamiltonian (control theory) , phonon , physics , ion , thermal conduction , quantum mechanics , superconductivity , mathematical optimization , mathematics
The multielectron operators (MEO) method is used for calculating the collective excitations of unfilled shells in transition ions. The excitation dispersion law depends on a chemical bond. Decrease of the lattice stability with increasing T is determined by the MEO correlation function of the neighbour sites (the order parameter). The conduction electron scattering on such excitations provides a contribution to the electrical resistance ϱ( T ) ∼ T 2 in a parabolical dispersion law approximation. The effective Hamiltonian is obtained of the Cooper pairing which energy is large enough for interaction of the conduction electrons with the nearest neighbour ions. The pairing mechanism is attenuated for antiferromagnetic spin ordering of the neighbour sites. The elastic moduli defect, determining a kink of the phonon contribution to ϱ( T ) near T c or T N , is taken into account, comparing the theory with the experimental curves ϱ( T ).