Dresden 2003 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 19: Supraleitung: Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter II

TT 19.1: Vortrag

Donnerstag, 27. März 2003, 14:30–14:45, HSZ301

From Static Magnetic Stripes to Superconductivity: High-Pressure µSR studies on La_1.8−xEu_0.2Sr_xCuO₄ — •H.-H. Klauss¹, D. Baabe¹, D. Mienert¹, H. Luetkens¹, A. Bosse¹, F.J. Litterst¹, B. Büchner², M. Hücker³, D. Andreica⁴, and A. Amato⁵ — ¹Institut für Metallphysik und Nukleare Festkörperphysik, TU Braunschweig — ²II. Physikalisches Institut, RWTH Aachen — ³Physics Department, Brookhaven National Laboratory, Upton, USA — ⁴Faculty of Physics, Babes-Bolyai University, Clui-Napoca, Romania — ⁵Paul Scherrer Institut, Villigen, Switzerland

The phase diagram of LTT structure La_1.8−xEu_0.2Sr_xCuO₄ resembles the generic cuprate phase diagram where the superconductivity is replaced by a magnetic stripe phase (PRL 85 (2000) 4590). At a charge doping of x = 0.2 a crossover from magnetic order to superconductivity has been found. We present new experiments showing that the ground state at x = 0.2 can be tuned from magnetism to superconductivity by a variation of the LTT lattice distortion. This is achieved by the application of hydrostatic pressure p < 1.2 GPa or by variing the Eu content between 0.23 and 0.10. Combining zero field and transverse field µSR we monitor the order parameter and volume fraction of the magnetic phase as well as the superconducting order parameter. The results reveal a first order transition between the different electronic ground states.