Regensburg 2002 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 4: Supraleitung: Massivmaterialien, Bandleiter, Pinning, Vortexdynamik, Transporteigenschaften, Korngrenzen

TT 4.10: Vortrag

Montag, 11. März 2002, 16:45–17:00, H18

Evidence for the formation of magnetic moments in the cuprate superconductor Hg_0.8Cu_0.2Ba₂Ca₂Cu₃O_3+δ below T_c seen by NQR — •Hergen Breitzke and Klaus Lüders — Fachbereich Physik, Freie Universität Berlin, 14195 Berlin

We report ^63/65Cu nuclear quadrupole resonance (NQR) measurements on the three layer high-T_c-superconductor Hg_0.8Cu_0.2Ba₂Ca₂Cu₃O_8+δ with T_c = 134 K. Below T_c we find a splitting of the ^63/65Cu NQR lines due to the presence of an internal magnetic field in the Cu₂O planes. This is further proved by the analysis of the longitudinal (T₁) and transverse (T₂) relaxation time, respectively. The value of the observed magnetic field is approximately 100 G. Our results favor the occurrence of a d-density wave (flux phase) as an origin of the observed magnetic field.