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 properties of Cr +2.9 at.% Al thin films

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

Kramer Law building

UCT Middle Campus Cape Town
Board: A.191
Poster Presentation Track A - Division for Physics of Condensed Matter and Materials Poster Session (1)

Speaker

Ms patience mudau (University of Johannesbug)

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>

Cr is an itinerant antiferromagnet with an incommensurate spin density wave structure, have an electron to atom ratio (e/a) of six and exhibits a Néel transition at TN = 311K [1]. If Cr is doped with elements with e/a > 6 an increase in TN is observed, while doping Cr with elements whose e/a < 6 results in TN decreasing [1]. However, despite the fact that Al has an e/a = 3, the Cr-Al magnetic phase diagram rather shows a sharp decrease in TN values, reaching a minimum near 2 at.% Al, where after the TN values unexpectedly increase [1, 2]. As thin films of Cr and its alloys show properties not observed in the bulk [3], this study extends existing knowledge through an investigation on Cr-Al alloy thin films. Cr97.1Al2.9 thin films of thickness 23 to 368 nm were deposited on fused silica, MgO(100) and MgO(110) using the DC magnetron sputtering techniques. X-ray diffraction was used to determine the structural properties of the films. Results obtained shows epitaxial growth for the films prepared on MgO, while those prepared on fused silica substrates are polycrystalline. Magnetic transition temperatures were obtained using standard four-point probe resistivity (&rho) as function of temperature (T) measurements. For samples deposited on fused silica no anomalies in ρ(T) associated with the TN are observed. ρ(T) curves for the films deposited on MgO showed weak anomalies in a form of domes associated with TN. In some cases these anomalies were weak resulting in difficulties in obtaining TN values. Interestingly, TN values found correlate well with those found in the magnetic phase diagram of bulk Cr-Al.
[1] E Fawcett et al. Rev. Mod. Phys. 66 (1994) 25
[2] CJ Sheppard et al. J. Alloys Compd. 595 (2014) 164
[3] HJ Zabel, J.Phys.: Condens. Matter 11(1999) 9380

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD, N/A)?

MSc

Please indicate whether<br>this abstract may be<br>published online<br>(Yes / No)

yes

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

yes

Main supervisor (name and email)<br>and his / her institution

Dr CJ Sheppard cjsheppard@uj.ac.za
University of Johannesburg

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

yes

Primary author

Ms patience mudau (University of Johannesbug)

Co-authors

Prof. Aletta Prinsloo (University of Johannesburg) Dr Andrew Venter (Necsa Limited) Dr Charles Sheppard (Department of Physics, University of Johannesburg) Prof. Eric Fullerton (University of California San Diego)

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