Far-infrared absorptivity of UPt/sub 3/

Journal Article · Thu Sep 15 00:00:00 EDT 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.38.5338· OSTI ID:6843469

Sulewski, P E; Sievers, A J; Maple, M B; Torikachvili, M S; Smith, J L; Fisk, Z

The absorptivity of the heavy-fermion compound UPt/sub 3/ is measured from 2 to 1000 cm/sup -1/ (0.25--124 meV) at temperatures between 1.2 K and room temperature. Above 50 cm/sup -1/ (6.2 meV) the absorptivity is relatively temperature independent, while below that frequency the absorptivity is very temperature dependent, in accord with the dc resistivity. By performing a Kramers-Kronig transformation of the data, augmented with recently published results at higher frequencies, the complex conductivity is obtained. The low-temperature conductivity may be characterized by free carriers which undergo frequency-dependent scattering and have a concomitant frequency-dependent mass enhancement, lambda(..omega..), with lambda(0) = 65. The data indicate a bare free-carrier plasma frequency of 2.1 x 10/sup 4/ cm/sup -1/ (2.6 eV). Combining these results with the measured specific heat for UPt/sub 3/ gives for the low-frequency effective mass m/sup */ = 240m, and for the optical band mass m/sub b/ = 3.7m. The carrier density is close to one electron per formula unit. The far-infrared absorptivity measurement indicates that the scattering rate begins to rise with an ..omega../sup 2/ dependence, while the measured dc resistivity has a T/sup 2/ dependence at temperatures below 2 K. To account for the far-infrared data, the carrier scattering rate GAMMA(..omega..,T) can be written as GAMMA(..omega..,T)approx...omega../sup 2/+(p..pi..T)/sup 2/, with an experimental upper limit of p = 1. This is not consistent with electron-electron scattering, for which p = 2.

• Research Organization: Laboratory of Atomic and Solid State Physics and Materials Science Center, Cornell University, Ithaca, New York 14853-2501
• OSTI ID: 6843469
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 38:8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
PLATINUM COMPOUNDS
ABSORPTIVITY
ELECTRIC CONDUCTIVITY
URANIUM COMPOUNDS
FAR INFRARED RADIATION
FREQUENCY DEPENDENCE
LOW TEMPERATURE
MEDIUM TEMPERATURE
TEMPERATURE DEPENDENCE
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
ACTINIDE COMPOUNDS
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
INFRARED RADIATION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
TRANSITION ELEMENT COMPOUNDS
360104* - Metals & Alloys- Physical Properties