Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 17: Magnetic Materials II
MA 17.10: Vortrag
Dienstag, 28. März 2006, 12:30–12:45, HSZ 401
Crystal growth and physical properties of cuprates grown under high pressure — •Nadja Wizent1, Günther Behr1, Lutz Schramm1, Mircea Apostu1, Anja Waske1, Thomas Doerte2, Michael Ruck2, Bernd Büchner1, and Wolfgang Löser1 — 1Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Germany — 2Technische Universität Dresden Institut für Anorganische Chemie Dresden, Germany
The copper oxide-based compounds are known for interesting properties like superconductivity, spin and charge ordering. Single crystals of cuprates with Co and Ca were grown with the travelling floating zone method under high oxygen pressure. Phase diagram studies were carried out on the basis of CALPHAD calculations. Magnetic and heat capacity measurements were accomplished on as grown and annealed crystals. Different growth strategies and heat treatments for the metastable phase CoCu2O3 were elaborated, which show the striking effect of growth rate on the constitution. A CaCu2O3 type phase was grown under 50 bar oxygen pressure with the composition of (Ca0,75Cu0,25)Cu2O3. Magnetic measurements revealed antiferromagnetic ordering below TN= 31 K . From structure investigations it is concluded that 11% of all Cu-atoms are on Ca-sites. Whereas, only 1/3 of them display magnetic moments.