Spin dynamics of the cerium and uranium monopnictides studied by neutron scattering (invited)

Journal Article · Tue Mar 20 00:00:00 EST 1984 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.333501· OSTI ID:5256028

Haelg, B; Furrer, A

The spin dynamics of the cerium and uranium monopnictides studied by diffuse and inelastic neutron scattering is reviewed. The diffuse scattering above the antiferromagnetic ordering temperature largely corresponds to longitudinal spin fluctuations which are highly anisotropic. For CeAs, CeSb, and UAs multicritical behavior has been found, i.e., the symmetry of the critical scattering above T/sub N/ differs from the actual type of magnetic ordering below T/sub N/. In the ordered state the magnetic excitation spectrum of UN and UAs exhibits only a broad response, whereas well defined spin-wave branches have been observed for USb and the cerium monopnictides. A very detailed study of the magnetic excitations has been performed for CeAs, where the spin-wave dispersion is split into two modes of transverse polarization due to the exchange anisotropy. One of these modes exhibits nearly zero energy gap and quadratic dispersion which has not previously been observed in antiferromangets. A generalized random-phase-approximation calculation taking into account anisotropic exchange interactions consistently describes the transverse magnetic excitations for TT/sub N/. In USb, CeSb, and CeBi the magnetic excitations display similar feature as the spin-waves in CeAs and can be understood in close analogy to the treatment applied to CeAs.

• Research Organization: Institut fuer Reaktortechnik, ETH Zuerich, CH-5303 Wuerenlingen, Switzerland
• OSTI ID: 5256028
• Journal Information: J. Appl. Phys.; (United States), Vol. 55:6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM COMPOUNDS
NEUTRON DIFFRACTION
SPIN WAVES
URANIUM COMPOUNDS
ANISOTROPY
ANTIFERROMAGNETISM
DISPERSION RELATIONS
EXCHANGE INTERACTIONS
GROUP THEORY
INELASTIC SCATTERING
PNICTIDES
RANDOM PHASE APPROXIMATION
RENORMALIZATION
ACTINIDE COMPOUNDS
COHERENT SCATTERING
DIFFRACTION
INTERACTIONS
MAGNETISM
MATHEMATICS
RARE EARTH COMPOUNDS
SCATTERING
360603* - Materials- Properties