Theory of magnetic properties of actinide compounds. I

Journal Article · Thu Nov 01 04:00:00 EST 1973 · Phys. Rev., B, v. 8, no. 9, pp. 4333-4347

DOI:https://doi.org/10.1103/PhysRevB.8.4333· OSTI ID:4323937

Robinson, J M; Erdos, P

UP, UAs, NpC, and crystals of other actinide compounds have metallic conductivity and are magnetically ordered. They exhibit discontinuous changes in the magnetic moment per actinide ion as a function of temperature. These are accompanied by large changes of the specific heat, magnetic susceptibility, and electrical conductivity, as well as in some cases by changes in the magnetic symmetry. The transition at the Neel temperatures may also be of first order. A theory is developed that explains these phenomena quanitatively. Abandoning the concept of a specific configuration (valency) of the actinide lon, we show that the transition 5f/sup h/ yields 5f/sup h-1/ (6d-7s)/sup 1/ occurs for a c ertain fraction of the ions ai different temperatures. The transition is induced by the combined effect of a small energy gap (or overlap) between the Sf localized and 6d-7s band states, the shielded and therefore short-range Coulomb interaction between band and localized electrons, and the variation of the exchange interaction between ions with the occupation of the band. The free energy is miminized with respect to the occupation numbers of the band states and of the magnetic sublevels of the ions in the two different configurations. This yields the temperature dependence of the band occupation and sublattice magnetization. The other observables are calculated from these quantities and fit thc experimental data well. (auth)

• Research Organization: Department of Physics, The Florida State University, Tallahassee, Florida 32306
• Sponsoring Organization: USDOE
• NSA Number: NSA-29-021603
• OSTI ID: 4323937
• Journal Information: Phys. Rev., B, v. 8, no. 9, pp. 4333-4347, Journal Name: Phys. Rev., B, v. 8, no. 9, pp. 4333-4347; ISSN PLRBA
• Country of Publication: United States
• Language: English

Related Subjects

*ACTINIDE COMPOUNDS-- TRANSITION TEMPERATURE
ANTIFERROMAGNETISM
ANTIMONY COMPOUNDS
ARSENIDES
BAND THEORY
CARBIDES
FERMI LEVEL
FERROMAGNETISM
N50330* --Metals
Ceramics
& Other Materials--Plastics & Other Materials--Properties
Structure & Phase Studies
NEPTUNIUM COMPOUNDS
NITRIDES
PHOSPHIDES
SULFIDES
URANIUM COMPOUNDS