Dynamical splitting of cubic crystal field levels in rare-earth cage compounds - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Physical Review B Année : 2019

Dynamical splitting of cubic crystal field levels in rare-earth cage compounds

Mehdi Amara

Résumé

The crystalline electric field (CEF) influence is usually described by considering an ideally symmetrical rare-earth site. In the case of cage compounds, ample excursions of the rare earth inside the cage require an adapted CEF description. A corrective, position-dependent, CEF term accounts for the deviation from the perfect symmetry. In the paramagnetic range, a CEF level with orbital degeneracy thus acquires a width reflecting the rare-earth spatial distribution. In the case, frequent in cubic systems, of an orbitally degenerate CEF ground state at the center, this width introduces an additional energy scale, influential at low temperature. A spherical simplification allows to identify the major consequences of a cage-split ground multiplet: a Schottky-type anomaly appears in the specific heat with associated reduction of the magnetic entropy and alteration of the magnetic properties. Concomitantly, a centrifugal Jahn-Teller effect develops that expands the distribution of the magnetic ion and softens the rattling phonons. These effects are confronted with anomalous paramagnetic properties of rare-earth cage compounds, notably rare-earth-filled skutterudites and hexaborides.
Fichier principal
Vignette du fichier
Dynamical splitting of cubic crystal field levels.pdf (950.27 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-02125893 , version 1 (10-05-2019)

Identifiants

Citer

Mehdi Amara. Dynamical splitting of cubic crystal field levels in rare-earth cage compounds. Physical Review B, 2019, 99 (17), pp.174405. ⟨10.1103/PhysRevB.99.174405⟩. ⟨hal-02125893⟩

Collections

UGA CNRS NEEL
27 Consultations
148 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More