SAIP 2011 Support
Crystalline Electric Field Effects in PrNiGe2
Presented by Mr. Jasper Snyman SNYMAN on 13 Jul 2011 from 17:00 to 19:00
Type: Poster Presentation
Track: Track A - Condensed Matter Physics and Material Science
<p>Within the confines of the standard model of rare earth magnetism, the high temperature magnetic properties of rare earth ions in a crystalline environment are identical to the magnetic behaviour of free tri-positive rare earth ions. At low temperatures deviations from free-ion behaviour occur due to the action of an anisotropic crystalline electric field (CEF). For Pr<sup>3+</sup>-ions in a low symmetry crystalline environment it is expected that the 9-fold degeneracy of the spin orbit coupled ground state multiplet associated with the free tri-positive ion should be completely uplifted by the CEF yielding a non-magnetic singlet ground state for the Pr<sup>3+</sup> 4f-electrons. PrNiGe<sub>2</sub> is known to order ferromagnetically despite the fact that the Pr<sup>3+</sup> ions occupy the low-symmetry m2m sites in the CeNiSi2-type structure. This has prompted the current study into the ground state properties of PrNiGe<sub>2</sub>. The structure of the CEF-split energy levels in this system could be determined from specific heat measurements. The analyses point to the formation of a pseudo-doublet ground state in the system, and we forward a conceptual explanation of the observed magnetic order in PrNiGe<sub>2</sub> in terms a fortuitous merging of electronic singlet levels into a local level dispensation of higher degeneracy.
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