Magnetism and superconductivity in high temperature superconducting cuprates





The high temperature copper oxide superconductors show several intricate phases as a function of doping concentration, temperature, and applied magnetic field. With doping of holes or electrons, the antiferromagnetism in the parent compounds is suppressed and the system goes through several phase transitions from antiferromagnetic insulating to metallic to superconducting, and then back to metallic again.  In the underdoped regime the metallic state exhibits very unusual properties, while in the overdoped region normal Fermi liquid behavior is found.  Field-dependent neutron scattering measurements in the electron-doped materials have been used to establish that in the underdoped pseudogap regime the competing ground state to (field-suppressed) superconductivity is antiferromagnetic and insulating.  These investigations have also revealed that these doped systems are intrinsically inhomogeneous on the nanoscale.  For the hole-doped materials our very recent polarized neutron measurements challenge the report that the formation of the pseudogap originates from a hidden magnetic order of circulating currents.




Presenter: Hye Jung Kang

Mentor: Jeffrey Lynn

Division: 856

Laboratory: NIST Center for Neutron Research

Neutron Condensed Matter Science

Room and Building: Room A116, Building 235

Mail Stop: 8562

Telephone: 301 975 4863

Fax: 301 869 4770


Sigma Xi member: No

Category:  Physics