The hyperfine interactions in high-Tc superconductors. Experiments and calculations

Ab initio study of the 57Fe quadrupole splitting in the heme models of α- and β-subunits in tetrameric deoxyhemoglobin

“…Atomic orbital populations (P), effective charges (Q eff ) and magnetic moments of atoms (μ) as well as model densities of electronic states (DOS) were calculated. Electric field gradient (EFG) and contributions to EFG from electrons (q el ) and lattice (q lat ) as well as quadrupole splitting (ΔE Q ) were calculated as following [12]: (5) 105.36 106.15 N porph (4)-Fe-N his (5) 106.58 100.96 N porph (1)-Fe-N porph (4) 89.61 90.03 N porph (1)-Fe-N porph (2) 85.17 88.50 N porph (2) where Q is nuclear quadruple moment, Q=0.16 barn for 57 Fe [13], q zz is the maximum value of diagonalized EFG, h ¼ qxxÀqyy j j qzz is the asymmetry parameter. EFG tensor was determined by equation:…”

Xα‐DVM modelling of oxygen transport in YBa2Cu3O7‐δ and SrFeO3

“…As a result, oxygen atoms get into the crystal structure of the tetragonal YBa 2 Cu 3 O 6 from the external gas phase and form the O phase of YBa 2 Cu 3 O 7 . Earlier we investigated the peculiarities of the electronic structure and parameters of electronic‐nuclear hyperfine interactions of 57 Fe and 63/65 Cu nuclei in YBa 2 (Cu 1‐ x Fe x ) 3 O 7‐δ 4 employing the X α ‐discrete variation method ( X α ‐DVM). However, the energy parameters of diffusion processes in this compound were not studied.…”

The forming factors of high values of superconducting transition temperature Tc in 3d-transition metal compounds I. The main groups of known superconductors

“…According to [6], the first superconducting perovskite structure was The data on the conductivity of most simple and perovskite-type oxide compounds are summarized in several reviews [7,8]. A number of perovskites that exhibit high-temperature superconductivity, includes YBa 2 Cu 3 O 7 (1-2-3) [9], bismuth (Bi) [10], thallium (Tl) [11], plumbum (Pb) [12] ceramics.…”

“…When you replace part of the copper atoms (Cu) on the atoms of cobalt (Co) T c even increases from 92 K in the undoped sample to 94.3 K for x = 0,05 in YBa 2 Cu 3-x Co x O 7-y [15]. A full review of the possible substitutions in the structure of superconducting based on copper ceramics for the period up to 1993 is presented in [8].…”