Dresden 2014 – scientific programme

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MA: Fachverband Magnetismus

MA 15: Spin structures and Magnetic Phase Transitions

MA 15.12: Talk

Tuesday, April 1, 2014, 12:30–12:45, HSZ 403

Evidence of spin-charge correlation and its interplay with superconductivity in 1/8-doped La_2−xSr_xCuO₄ and La_2−xBa_xCuO₄ – a ¹³⁹La spin-lattice relaxation study — •Seung-Ho Baek¹, Markus Hücker², Andreas Erb³, Genda Gu², Bernd Büchner¹, and Hans-Joachim Grafe¹ — ¹IFW-Dresden, Institute for Solid State Research, PF 270116, 01171 Dresden, Germany — ²Brookhaven National Laboratory, Upton, New York 11973, USA — ³Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Straße 8, D-85748 Garching, Germany

We discuss the ¹³⁹La nuclear magnetic resonance (NMR) spin-lattice relaxation rate T₁⁻¹ of La_2−xSr_xCuO₄ (LSCO:x, 0.07≤ x ≤ 0.15) as well as 1/8-doped La_2−xBa_xCuO₄ (LBCO:1/8) single crystals. A doping of 1/8-holes induces an unusual spin freezing behavior which, though much weaker, resembles stripe-ordered LBCO:1/8. Together with previous ¹³⁹La T₁⁻¹ data of La_1.8−xEu_0.2Sr_xCuO₄ (LESCO), we provide compelling evidence that charge order is closely connected with spin freezing occurring in ∼1/8-doped La cuprates. The unconventional external field dependence of the spin freezing in LSCO:1/8, which is absent in non-superconducting LESCO:0.13 and LBCO:1/8, suggests a competing relationship between charge order and superconductivity.