Strong Electron Corrections in Short-range Magnetic Order and Electrical Resistance of Homogeneously Disordered Binary Crystals

• Main Authors: Repetsky, S.P., Tatarenko, V.A., Melnyk, I.M., Len, E.G.
• Format: Article
• Language: English
• Published: Відділення фізики і астрономії НАН України 2010
• Series: Український фізичний журнал
• Subjects: Тверде тіло
• Online Access: http://dspace.nbuv.gov.ua/handle/123456789/56194

The formation of both the short-range magnetic order and the electrical conductivity in homogeneously disordered binary crystals under the influence of strong electron correlations is considered (by the example of b.c.c.-Fe1-cCoc alloys). For the description of electron states in a crystal, the multiband model of a tight binding and the method of the cluster expansion for Green’s functions and the thermodynamic potential of a disordered crystal are used. Strong electron correlations and the well-developed short-range order of substitutional atoms lead to the appearance of a quasigap in the electron-energy spectrum. The microscopic mechanisms of magnetic ordering and formation of the electrical resistance are concerned with both the Fermi-level position within the quasigap region and the realignment of the electron-energy spectrum with changes of the temperature or the alloying-component concentration. The parameter of pairwise magnetic correlations decreases with increase in the temperature and tends to zero in a vicinity of the Curie temperature. The nonmonotonic concentration dependence of the Fe-Co-alloy electrical resistance is investigated as well. It is caused by strong electron correlations and the magnetic order resulting from these correlations.