25 citations · 101 across the 38 of their papers we have counts for
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Model for the FC and ZFC Ferrimagnetic Spinel
N. Karchev
There are two methods of preparation of ferrimagnetic spinel. If, during the preparation, an external magnetic field as high as 300 Oë is applied upon cooling the material is named…
Coexistence of superconductivity and magnetism in spin-fermion model of ferrimagnetic spinel in an external magnetic field
Naoum Karchev
A two-sublattice spin-fermion model of ferrimagnetic spinel, with spin- itinerant electrons at the sublattice site and spin- localized electrons at the sublattice s…
Leggett's Modes in Magnetic Systems with Jahn-Teller distortion
Naoum Karchev
Leggett's mode is a collective excitation corresponding to the oscillation of the relative phase of the order parameters in a two band superconductor, with frequency proportional t…
Path integral representation for spin systens
Naoum Karchev
The present paper is a short review of different path integral representations of the partition function of quantum spin systems. To begin with, I consider coherent states for SU(2…
Ferromagnetic Quantum critical behavior in three-dimensional Hubbard model with transverse anisotropy
Naoum Karchev
One-band Hubbard model with transverse anisotropy is considered at density of electrons . It is shown that when the anisotropy is appropriately chosen, the ground state is f…
Quantum critical behavior in three-dimensional one-band Hubbard model at half filling
Naoum Karchev
One-band Hubbard model with hopping parameter and Coulomb repulsion is considered at half filling. By means of the Schwinger bosons and slave Fermions representation of the…