7-11 July 2014
Africa/Johannesburg timezone
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Magnetic susceptibility studies of the (Cr98.4Al1.6)100-xMox alloy system

Presented by Mr. Blessed MUCHONO on 8 Jul 2014 from 17:10 to 19:00
Type: Poster Presentation
Session: Poster1
Track: Track A - Division for Physics of Condensed Matter and Materials
Board #: A.121

Abstract

The magnetic behaviour of the Cr<sub>100-<i>y</i></sub>Al<sub><i>y</i></sub> alloy system around the triple point concentration <i>y</i><sub>t</sub> ≈ 2 has recently attracted renewed interest amongst Cr alloys [1]. The temperature of the triple point concentration on the Cr<sub>100-<i>y</i></sub>Al<sub><i>y</i></sub> magnetic phase diagram can be suppressed to below 2 K by the addition of Mo for <i>y</i> fixed at 1.6 at.% Al to form a (Cr<sub>98.4</sub>Al<sub>1.6</sub>)<sub>100-<i>x</i></sub>Mo<sub><i>x</i></sub> ternary alloy system. Previous studies on the (Cr<sub>98.4</sub>Al<sub>1.6</sub>)<sub>100-<i>x</i></sub>Mo<sub><i>x</i></sub> alloy system through electrical resistivity (<i>ρ</i>), Seebeck coefficient (<i>S</i>) and specific heat (<i>C</i><sub>p</sub>) showed the existence of a possible quantum critical point around 4.5 at.% Mo [2]. The present study was undertaken in order to extend the previous findings on this alloy system, through magnetic susceptibility (<i>χ</i>) measurements. Samples in the form of cylindrical discs were cooled from 300 K to 4 K in a zero magnetic field. Measurements were then taken from 4 K to 300 K in a constant magnetic field of 100 Oe. Alloys in the concentration range 0 ≤ <i>x</i> ≤ 3.0 depict anomalous <i>χ</i>(<i>T</i>)-behaviour in the temperature range of the Néel transition. This is attributed to local magnetic moments formed around the impurity atoms [3]. Néel temperatures obtained from <i>χ</i>(<i>T</i>) measurements decrease with Mo concentration and disappear near a critical concentration <i>x</i><sub>c</sub> = 4.5, where antiferromagnetism is suppressed to below 4 K. The present results corroborate the previous findings on this alloy system [2]. [1] Sheppard C J, Prinsloo A R E, Alberts H L, Muchono B and Strydom A M 2014 J. Alloys and Compounds 595 164 [2] Muchono B, Prinsloo A R E, Sheppard C J, Alberts H L and Strydom A M 2014 J. Magn. Magn. Mater. 354 222 [3] de Oliveira L M, Ortiz W A and de Oliveira A J A 2003 J. Appl. Phys. 93 7154

Award

Yes

Level

PhD

Supervisor

Prof. A.R.E. Prinsloo, Physics Department, University of Johannesburg, alettap@uj.ac.za

Paper

Yes

Place

Room: D Ring ground level


Primary authors

  • Mr. Blessed MUCHONO University of Johannesburg, National University of Science and Technology
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Co-authors

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