Neutron Scattering on. High Transition Temperature Superconductors Miaoyin Wang Solid State Physics II: Presentation II Apr., 2010 @ UTK. Outline. 1. High T c Superconductor 2. Neutron Scattering 3. Neutron Scattering on High T c Superconductor. 1. Superconductor.
High Transition Temperature
Solid State Physics II: Presentation II
Apr., 2010 @ UTK
1. High Tc Superconductor2. Neutron Scattering3. Neutron Scattering on High Tc Superconductor
*Resistance = 0 at Tc*Meissner Effect
Songxue Chi et al., PRL
*More Magnetic Field …
BCS Theory = Bardeen & Cooper & Schrieffer
More system to compare
Cu is not so special!
Shiliang Li et al., Wuli
S. Chi et al., PRL
Shiliang Li et al., PRB
Property: Doping & Phase Diagram
>Go deep into sample – a bulk detector
>Nuclear / Magnetic Structure
For Neutron Energy ~ 1meVWavelength ~ 0.1-1 nm
Neutron Loves H!
Be aware of plastic...
From NCNR Website
Neutron ScatteringWhat we are interested in?1. Elastic & Inelastic2. Energy & Momentum (transfer)3. Intensity
Structure 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 peak
About Instrument: Powder Diffractometry
HB-2A in HFIR, ORNL
What the data look like…
What we have found…
Structure distortion1. Suppressed like AFM order by doping.2. Totally disappear in SC phase.
What we have found…
Resonance 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-δ2. Inelastic3. Spin resonance
About Instrument: Triple-axis Spectrometry
BT-2 in NCNR, NIST
1.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.