Electronic and mechanical properties of collective-mode conductors

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:7005590

Bourne, L C

The author measured the elastic properties of the collective mode conductors K{sub 0.3}MoO{sub 3}, URu{sub 2}Si{sub 2} and La{sub 2-x}Sr{sub x}CuO{sub 4}. K{sub 0.3}MoO{sub 3} has an anisotropic modulus anomaly at the Charge-Density-Wave (CDW) transition temperature compared to a theoretical model of CDW formation; also, no change was found in elastic properties from CDW depinning. URu{sub 2}Si{sub 2} has anomalies in both the modulus and the dissipation near 18 K due to the formation of a Charge- or Spin-Density Wave. La{sub 2-x}Sr{sub x}CuO{sub 4} shows a dramatic lattice softening that may be related to the superconducting mechanism, and a small modulus anomaly at T{sub c} used to predict the corresponding specific heat anomaly. The elastic properties of the CDW conductors TaS{sub 3} and NbSe{sub 3} have been measured in the presence of ac, dc, and combined ac and dc electric fields. For both materials, the application of ac fields E{sub ac} in the MHz range softens the crystal lattice. The author substituted isotopes of oxygen, barium, and copper in the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 7} and isotopes of oxygen in La{sub 1.85}Sr{sub 0.15}CuO{sub 4}. The measured shifts in T{sub c}'s are much smaller than those expected from the conventional BCS phonon-induced electron pairing mechanism.

• Research Organization: California Univ., Berkeley, CA (USA)
• OSTI ID: 7005590
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
360603 -- Materials-- Properties
ACTINIDE COMPOUNDS
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
CUPRATES
ELASTICITY
ION EXCHANGE
LANTHANUM COMPOUNDS
MECHANICAL PROPERTIES
MOLYBDATES
MOLYBDENUM COMPOUNDS
NIOBIUM COMPOUNDS
NIOBIUM SELENIDES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
RUTHENIUM COMPOUNDS
RUTHENIUM SILICIDES
SELENIDES
SELENIUM COMPOUNDS
SILICIDES
SILICON COMPOUNDS
STRONTIUM COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
SUPERCONDUCTORS
TANTALUM COMPOUNDS
TANTALUM SULFIDES
TENSILE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
URANIUM COMPOUNDS
URANIUM SILICIDES
YTTRIUM COMPOUNDS