Neutron Scattering onSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Neutron Scattering onHigh Transition TemperatureSuperconductorsMiaoyin WangSolid State Physics II: Presentation IIApr., 2010 @ UTK1. High Tc Superconductor2. Neutron Scattering3. Neutron Scattering on High Tc SuperconductorOutline1. SuperconductorSongxue Chi et al., PRL*Resistance = 0 at Tc*Meissner Effect1. Superconductor*More Magnetic Field …1. SuperconductorBCS Theory = Bardeen & Cooper & Schrieffer2. High-Tc SuperconductorFrom Wikipedia2. High-Tc SuperconductorProperty:StructureShiliang Li et al., WuliShiliang Li et al., PRBS. Chi et al., PRL2. High-Tc SuperconductorProperty: Doping & Phase Diagram3. Neutron ScatteringNeutron:No Charge>Go deep into sample – a bulk detectorSpin 1/2>Nuclear / Magnetic StructureFor Neutron Energy ~ 1meVWavelength ~ 0.1-1 nm3. Neutron ScatteringNeutron Cross-SectionFrom NCNR Website3. Neutron ScatteringNeutron ScatteringWhat we are interested in?1. Elastic & Inelastic2. Energy & Momentum(transfer)3. Intensity4. Experiment No.1Structure and magnetic phase diagram of CeFeAsO1-xFx and its relation to high-temperature superconductivityJun Zhao et al., Nature Materials 7 , 953-959 (2008). About Experiment1. Powder Sample CeFeAsO1-xFx2. Elastic3. Nuclear / Magnetic Bragg peak4. Experiment No.1About Instrument: Powder DiffractometryHB-2A in HFIR, ORNL4. Experiment No.1What the data look like…4. Experiment No.1What we have found…Structure distortion1. Suppressed like AFM order by doping.2. Totally disappear in SC phase.4. Experiment No.1What we have found…4. Experiment No.2Resonance in the electron-doped high-transition-temperature superconductor Pr0.88LaCe0.12CuO4-δWilson S D et al., Nature, 2006, 442:59 About Experiment1. Single Crystal Sample Pr0.88LaCe0.12CuO4-δ 2. Inelastic3. Spin resonance4. Experiment No.2About Instrument: Triple-axis SpectrometryBT-2 in NCNR, NISTkikfQ4. Experiment No.2Spin Resonance4. Experiment No.2Data4. Experiment No.2ResultSummary1.Structure distortion is strongly related to AFM order and superconductivity.2. Structure distortion is suppressed with doping, and vanishes in the SC phase.3. Spin Resonance independence with doping type (hole or electron).4. Resonance energy is always proportional to Tc, which suggests that the resonance is the universal feature in high-Tc superconductor.Thank you!Thank you!Thank you!Thank
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