Single crystal NMR of high temperature superconductors

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6718998

Pennington, C H

Cu NMR studies of the high temperature superconductor YBa2Cu3O(7-delta) (T sub c = 90 K) using a 1 mg single crystal is reported. Three types of measurements were made for both the plane and chain Cu crystallographic sites and with the static magnetic field placed successively along each of the three crystal axes a, b, and c: nuclear magnetic resonance (NMR) lineshapes, spin-lattice relaxation, and transverse relaxation. From these measurements four NMR tensors are deduced: the magnetic shift tensor, the electric field gradient tensor, the spin-lattice relaxation rate tensor, and the transverse relaxation rate tensor. As a preliminary matter, the symmetries of the magnetic shift and electric field gradient tensors were used to assign the two families of NMR lines to their respective crystallographic sites. From an analysis of the electric field gradient tensors it is shown that both the plane and chain Cu have valences Cu(2+), giving a single hold in the Cu atomic d-shell. The spin-lattice relaxation rate and magnetic shift of the plane and chain Cu were analyzed; included were both analyses in which only normal state data were considered, and in which superconducting state measurements of magnetic shifts were considered as well. These analyses show that the plane Cu atom behaves very nearly as a local moment. The chain Cu is probably also in the local moment limit; however, its NMR properties are largely determined by its interaction with oxygen holes in the chain.

• Research Organization: Illinois Univ., Urbana, IL (USA)
• OSTI ID: 6718998
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
DATA
ELECTRIC FIELDS
EXPERIMENTAL DATA
HIGH-TC SUPERCONDUCTORS
INFORMATION
MAGNETIC FIELDS
MAGNETIC RESONANCE
MONOCRYSTALS
NUCLEAR MAGNETIC RESONANCE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
RELAXATION
RESONANCE
SPIN-LATTICE RELAXATION
SUPERCONDUCTORS
TENSORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES