Münster 1997 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 19: Postersitzung III: Josephsonkontakte(1-25), SQUIDs, Sensoren, Detektoren(26-37), Supraleitung in Hochfrequenz und Elektronik(38-45), Präparation und Dotierung von HTSL(46-53), NMR und Ultraschall in HTSL(54-60), Thermodynamik, Magnetismus(61-68), Transporteigenschaften von HTSL(69-73), Spektroskopie, Ramanstreuung, param. Meissner-Effekt in HTSL(74-84), n-dotierte HTSL(85-91)
TT 19.65: Poster
Donnerstag, 20. März 1997, 15:30–19:00, Z1
Specific Heat of Pure Y1−xPrxBa2Cu3O7−δ Single Crystals in Magnetic Fields — •W. Schnelle1, S. Uma1,2, E. Gmelin1, G. Rangarajan2, and A. Erb3 — 1Max-Planck-Institut für Festkörperforschung, Stuttgart — 2Dept. of Physics, Indian Institute of Technology, Madras, India — 3DPMC, Université de Genève, Switzerland
Specific heat measurements have been performed on ab-plane twinned single crystals of Y1−xPrxBa2Cu3O7−δ (x=0.33,1) in the temperature range 0.3 K < T < 50 K with magnetic fields up to 7.5 T, both parallel and perpendicular to the c-axis. The crystals were grown in BaZrO3 crucibles and therefore the possibility of crucible contamination in the crystals is reduced to a large extent. A large linear term with γ* ≈ 200 mJ/mol K2 at 2K was determined for x=1 and the crystal field contribution of the Pr ion was calculated for both samples. The transitions were found to be sharp lambda type for x=1 with the ordering temperature TN = 16.6K and for x=0.33 with the transition temperature ≈ 0.75K. Also, the transition temperatures increased for x = 0.33 and decreased for x=1 with increasing magnetic fields indicating a different type of magnetic interaction for these two samples. The coupling in the ab-plane was found to be stronger than along the c-axis. For x=1 a splitting of the sharp peak at TN is observed for magnetic fields in the ab-plane.