4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=10&confId=86">The Proceedings of SAIP2016</a> published on 24 December 2017

Magnetic and Kondo behaviour in Ce8Pd24(Al1-xSnx)

5 Jul 2016, 16:10
1h 50m
Kramer Law building

Kramer Law building

UCT Middle Campus Cape Town
Board: A.253
Poster Presentation Track A - Division for Physics of Condensed Matter and Materials Poster Session (1)

Speaker

Prof. Moise Bertin Tchoula Tchokonte (Department of Physics, University of the Western Cape)

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

Ce8Pd24(Al1−xSnx ), (0≤ x ≤ 1) has been studied by magnetic susceptibility, (T), magnetization,
M(μ0H), electrical resistivity, ρ(T), thermoelectric power, S(T), and thermal conductivity, λ(T), measurements. All investigated compositions crystallize in a cubic AuCu3 – type crystal structure with space group Pm−3m (No. 221). (T) data at high temperature follows the paramagnetic Curie – Weiss relation with negative Weiss temperatures θp and effective magnetic moments μeff close to the value of 2.54 μB expected for the free Ce3+ - ion. The low temperature dc (T) data indicate an antiferromagnetic (AFM) anomaly for all compositions between 0 ≤ x ≤ 1, associated with a Néel temperature ranging from TN = 4.3 K to 6.9 K between the two end compounds. Field – cooling (FC) and zero – field – cooling (ZFC) (T) data indicates spin – glass behaviour at Al concentrated alloys. ρ(T) data is dominated by coherent Kondo lattice scattering for alloys in the concentration range 0 ≤ x ≤ 0.5 and by crystal –electric field (CEF) effect for alloys with x ≥ 0.7. At low temperature ρ(T) data indicate a steep decrease at TN associated with magnetic phase transition also observed in the (T) results. Below TN, ρ(T) is described by a spin – wave dispersion relation. At low temperatures, S(T) data measurements indicate an AFM transition at TN corresponding to the (T) and ρ(T) results. The high temperature S(T) data is described by the phenomenological resonance model giving the Kondo temperature TK and the characteristic temperature TCEF associated with crystal - electric field effect. λ(T) increase linearly with temperatures from low T. The reduced Lorentz number, L/L0 increase upon cooling and exhibit maxima which decrease in magnitude with increase x, while the figure of merit (ZT=S2T/ρ) exhibit maxima and minima upon cooling and the magnitude at room temperature decreases with x.

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Primary author

Prof. Moise Bertin Tchoula Tchokonte (Department of Physics, University of the Western Cape)

Co-authors

Mr Aiman Bashir (University of the Western Cape) Prof. Andre Michael Strydom (University of Johannesburg) Prof. Dariuzs Kaczorowski (Institute of Low Temperature and Structure Research, Polish Academiy of Sciences)

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