Spin-hole doping in the Kondo insulator Ce{sub 3}Bi{sub 4}Pt{sub 3} studied by neutron scattering

Conference · Wed Sep 01 00:00:00 EDT 1993

OSTI ID:10184651

Severing, A ^[1]; Perring, T ^[2]; Thompson, J D; Fisk, Z ^[3]; Canfield, P C ^[3]

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1. Institut Laue-Langevin, 38 - Grenoble (France)
2. Rutherford Appleton Lab., Chilton (United Kingdom)
3. Los Alamos National Lab., NM (United States)

To investigate the effect of non-magnetic impurities on gap formation and stability in Kondo insulators, we have performed inelastic neutron scattering experiments on (Ce{sub 1-x}La{sub x}){sub 3}Bi{sub 4}Pt{sub 3}, with x = 0.0, 0 1, 0.25 and 1.0. Data were collected at the Rutherford spallation source using incident neutron energies of 30 and 100 MeV and with the sample temperature fixed at 10K, well below {Delta}g/k{sub B}. The gap edge, defined from the rapid onset of scattering intensity, decreases quadratically with La content. However, the energy {Delta}{sub g} at which the magnetic intensity reaches one-half its maximum value scales with x and the temperature T{sub max} at which the static susceptibility is maximum. {Delta}g/k{sub B}T{sub max} is independent of x and equal to 2.5 {plus_minus} 0.1, a value curiously close to the total angular momentum of Ce{sup 3+}. Three important conclusions are drawn from the these observations: (1) As suggested theoretically, T{sub max} does provide a measure of the gap produced in the spin-excitation spectrum of Kondo insulators. (2) Creation of spin holes by thermal excitation or La substitution has comparable effects on the gap. (3) The existence of a spin gap even with significant perturbation in the Ce-sublattice periodicity suggests that coherence effects are not important for the existence of the gap and that spin dynamics are determined locally.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 10184651
• Report Number(s): LA-UR-93-2949; CONF-930865-4; ON: DE93040107; TRN: 93:023882
• Resource Relation: Conference: International conference on strongly correlated electron systems,La Jolla, CA (United States),16-19 Aug 1993; Other Information: PBD: [1993]
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
36 MATERIALS SCIENCE
CERIUM ALLOYS
NEUTRON DIFFRACTION
LANTHANUM ALLOYS
BISMUTH BASE ALLOYS
PLATINUM ALLOYS
ELECTRICAL INSULATORS
KONDO EFFECT
ANTIFERROMAGNETIC MATERIALS
INELASTIC SCATTERING
ENERGY GAP
SPIN
663430
360104
NUCLEON-INDUCED REACTIONS AND SCATTERING
PHYSICAL PROPERTIES