[sup 209]Bi NMR and NQR investigation of the small-gap semiconductor Ce[sub 3]Bi[sub 4]Pt[sub 3]

Journal Article · Wed Jun 15 00:00:00 EDT 1994 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.49.16321· OSTI ID:7205542

Reyes, A P; Heffner, R H; Canfield, P C; Thompson, J D; Fisk, Z ^[1]

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1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

We report measurements of the temperature dependence of the [sup 209]Bi nuclear quadrupole resonance frequency [nu][sub [ital Q]], the Knight shift [ital K], and the spin-lattice relaxation rate 1/[ital T][sub 1] in the small-gap semiconductor Ce[sub 3]Bi[sub 4]Pt[sub 3] between 1.8 and 300 K. Corresponding measurements also are reported for the nonmagnetic metallic isomorph La[sub 3]Bi[sub 4]Pt[sub 3]. The [nu][sub [ital Q]] data in the Ce compound show a characteristic departure from metallic-to-insulating behavior when the sample is cooled below [ital T][sub [ital M]]=80 K, the temperature of the susceptibility maximum, attributable to a loss of low-frequency vibrational modes in the insulating state. The Knight shift has both isotropic and axial components; this anisotropy originates from the presence of Ce via a transferred hyperfine coupling between Ce 4[ital f] and conduction electrons. An [ital s]-[ital f] exchange constant [ge]0.4 eV is found, consistent with hybridization in other rare-earth intermetallic compounds. A change in the scaling between the susceptibility and both the isotropic and axial Knight shifts at temperature [ital T][sub [ital M]] provides evidence that hybridization between the Ce 4[ital f] orbitals and the conduction electrons is responsible for the gap structure. The temperature dependence of the 1/[ital T][sub 1] data is consistent with a model electronic density of states possessing a temperature-independent gap [delta] of 180 K and a bandwidth of the order of 1600 K. The temperature dependence of 1/[ital T][sub 1] can also be fit well with a temperature-dependent gap with [delta](0) also [approx]180 K.

• OSTI ID: 7205542
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 49:23; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH ALLOYS
NUCLEAR QUADRUPOLE RESONANCE
CERIUM ALLOYS
PLATINUM ALLOYS
SEMICONDUCTOR MATERIALS
ENERGY GAP
HYPERFINE STRUCTURE
INTERMETALLIC COMPOUNDS
KNIGHT SHIFT
MAGNETIC SUSCEPTIBILITY
RELAXATION TIME
SPIN-LATTICE RELAXATION
TEMPERATURE DEPENDENCE
VIBRATIONAL STATES
ALLOYS
ENERGY LEVELS
EXCITED STATES
MAGNETIC PROPERTIES
MATERIALS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
RARE EARTH ALLOYS
RELAXATION
RESONANCE
360104* - Metals & Alloys- Physical Properties