Charge-carrier density and interplane coupling inY2Ba4

Lack of Evidence for Orbital-Current Effects in the High-TemperatureY2Ba4Cu7O15−δSuperconductor usingSträssle1, Roos2, Mali3 et al. 2008Phys. Rev. Lett.Self Cite301300View full textAdd to dashboardCite

“…As in Y124 and Y123 the CuO 2 planes in Y247 form bi-layers separated by Y ions. Unlike the parent compounds, the adjacent planes in Y247 are unequally doped [13]. As was pointed out by Lee and Sha this doping difference should to some extent prevent a possible cancellation of the staggered magnetic fields between bi-layers [12].…”

“…Ref. 13). Therefore, inhomogeneous doping should lead to a steady increase of the full Y LW in Y247, accompanied by a growing asymmetry of the line shape with decreasing temperature.…”

“…Lee and Sha proposed such NMR measurements in the cuprate superconductor Y 2 Ba 4 Cu 7 O 15−δ (Y247) [12]. This specific material exhibits a high transition temperature to superconductivity of T c = 95 K and shows a clear pseudogap phase above T c [13]. It consists of alternating YBa 2 Cu 3 O 7−δ (Y123) and YBa 2 Cu 4 O 8 (Y124) blocks.…”

“…Although results from neutron measurements favor an in-phase OC circulation [9,17], we assume anti-phase circulation because of the coupling between OC from adjacent planes, which increases the upper limit of the single plane field. The carrier density in Y247 for planes from both blocks (Y123 and Y124) has been deduced and a difference of ∼ 20% was determined [13]. We take the difference of the orbital-current strength j to be of the same order of magnitude, because j is inversely proportional to the doping level [4,18].…”

Interplane relaxation and the bilayer coupling in Y2Ba4Cu7O15

“…One plane of the bilayer is attached to the single chain block the other one to the double chain block. Some of the properties of this material have been studied by Stern et al 15 In particular they nd that the nuclear quadrupole resonance (NQR) frequencies of the Cu nuclear spins in the individual planes of the bilayers are di erent from each other. This allows one to access the spins in both CuO 2 planes seperately.…”