4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
Paper Review: Initial screening in progress
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Interplay of antiferromagnetic and Kondo effect in Ce8Pd24Al

Presented by Mr. Aiman BASHIR on 5 Jul 2016 from 16:10 to 18:00
Type: Poster Presentation
Track: Track A - Division for Physics of Condensed Matter and Materials
Board #: A.258

Abstract

The suppression of antiferromagnetic (AFM) order and Kondo effect in Ce<sub>8</sub>Pd<sub>24</sub>Al with the dilution of Ce with La is investigated by means of magnetic susceptibility, χ(T), magnetization, M(μ<sub>0</sub>H), electrical resistivity, ρ(T), magnetoresistivity, MR, thermoelectric power, S(T), and thermal conductivity, λ(T) measurements. X – ray diffraction studies indicate a cubic AuCu<sub>3</sub> – type crystal structure for all compositions on the alloys series (Ce<sub>1–x</sub> La<sub>x</sub>)<sub>8</sub>Pd<sub>24</sub>Al. At high temperature, χ(T) follows the paramagnetic Curie – Weiss behavior with negative paramagnetic Weiss temperatures θ<sub>p</sub> and effective magnetic moment μ<sub>eff</sub> values in close agreement with the value of 2.54 μ<sub>B</sub> expected for free Ce<sup>3+</sup> - ion. The low temperature dc χ(T) data show an AFM anomaly associated with a Néel temperature T<sub>N</sub> which decreases almost linearly from 4.2 K for x = 0 to 2.9 K for x = 0.2 alloys. For alloys in the concentration range of 0 ≤ x ≤ 0.3, ρ(T) is characterized by a coherent Kondo lattice scattering with a well-defined ρ(T) maximum at T<sub>max</sub> = 9 K to 5.1 K for compositions in the range 0 ≤ x ≤ 0.3, while incoherent single – ion Kondo scattering prevail for the x ≥ 0.4 alloys. MR measurements on Ce diluted alloys are analyzed based on the calculations by Schlottmann for the Bethe – ansatz in the frame of the Coqblin – Schrieffer model and yields values of the Kondo temperature T<sub>K</sub> and the effective moment of the Kondo ion μ<sub>K</sub>. The decrease in T<sub>K</sub> and T<sub>max</sub> is described by the compressible Kondo lattice model. S(T) measurements are interpreted within the phenomenological resonance model giving values of the characteristic temperature T<sub>CEF</sub> associated to crystal – electric field (CEF) effect. λ(T) data increase linearly with temperature from low temperature with T, while the reduced Lorentz number L/L<sub>0</sub> increase upon cooling and exhibit maxima at low temperature which decrease in magnitude with increased La content x.

Award

Yes

Level

PhD

Supervisor

Moise B. Tchoula Tchokonte; mtchokonte@uwc.ac.za; University of the Western Cape

Paper

Yes

Permission

Yes

Place

Location: Kramer Law building
Address: UCT Middle Campus Cape Town
Room:


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