4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
The Proceedings of SAIP2016 published on 24 December 2017
Home > Timetable > Session details > Contribution details
PDF | XML | iCal

Magnetic properties of Cr +2.9 at.% Al thin films

Presented by Ms. patience MUDAU 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.191

Abstract

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

Award

yes

Level

MSc

Supervisor

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

Paper

yes

Permission

yes

Place

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


Primary authors

More

Co-authors

More