Effects of magnetic field on the cuprate high-T-c superconductor La2-xSrxCuO4

This article discusses neutron scattering measurements on the cuprate, high transition temperature superconductor La2-xSrxCuO4 (LSCO) in an applied magnetic field. LSCO is a type-II superconductor and magnetic flux can penetrate the material via the formation of vorticies. Phase coherent superconductivity characterized by zero resistance is suppressed to the lower field-dependent irreversibility temperature (T-irr(H)) and occurs when the vortices freeze into a lattice. Because superconductivity is destroyed within the vortex cores, an investigation of the vortex state provides information about the ground state that would have appeared had superconductivity not intervened. Our measurements reveal that both optimally doped LSCO (x = 0.16, T-c = 38.5 K) and underdoped LSCO (x = 0.10, T-c = 29 K) have an enhanced antiferromagnetic response in a field. Measurements of the optimally doped system for H = 7.5 T show that inelastic sub-gap spin fluctuations first disappear with the loss of finite resistivity at T-irr, but then reappear at a lower temperature with increased lifetime and correlation length compared to the normal state. In the underdoped system elastic antiferromagnetism develops below T-c in zero field, and is significantly enhanced by application of a magnetic field; phase coherent superconductivity is then established within the anti- ferromagnetic phase at T-irr.

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Physica Status Solidi B-Basic Research, 241, 6, 1223-1228
Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ London Univ Coll, Dept Phys & Astron, London WC1E 6BT, England. NEC Res Inst, Princeton, NJ 08540 USA. Riso Natl Lab, Mat Res Dept, DK-4000 Roskilde, Denmark. CEA, MDN SPSMS DRFMC, F-38054 Grenoble 9, France. Hahn Meitner Inst Berlin GmbH, BENSC, D-14109 Berlin, Germany. Univ Tokyo, Grad Sch Frontier, Dept Adv Mat Sci, Tokyo 1138656, Japan. Loughborough Univ Technol, Dept Phys, Loughborough LE11 3TU, Leics, England. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Lake, B, Univ Oxford, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England. bella.lake@physics.ox.ac.uk

 Record created 2007-01-24, last modified 2018-03-17

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