7-11 July 2014
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=16&confId=34"><font color=#0000ff>SAIP2014 Proceedings published on 17 April 2015</font></a>

Synthesis, characterization and magnetic ordering of the semiconducting intermetallic compound FeGa<sub>3</sub>

9 Jul 2014, 17:10
1h 50m
D Ring ground level

D Ring ground level

Board: A.308
Poster Presentation Track A - Division for Physics of Condensed Matter and Materials Poster2

Speaker

Mr Mustafa Ahmed (University of Johannesburg)

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>

Intermetallic compounds which are formed by good conductive metals are usually metallic. However, FeGa3 was found to be a semiconductor with a narrow gap measured to be between 0.2 and 0.46 eV [1,2,3]. This gap mainly arises from the hybridization between the Ga 4p and Fe 3d bands [4]. The band-gap has been established experimentally by various techniques [4,5], and its origin verified by density functional theory (DFT) calculations [2,5].
FeGa3 crystallizes in the tetragonal space group P42/mnm (No. 136) [3]. The magnetism in this compound has not yet been observed, with various magnetization and specific heat measurements suggesting that it does not occur down to very low temperatures [4,6]. Recent work has also shown that the effect of the chemical doping on single crystal FeGa3 creates a spin 1/2 local moment and drives the compound to become metallic [7]. Mössbauer spectroscopy (MES) has shown the absence of an internal magnetic field at the site of Fe confirming that no ordering above room temperature occurs [3]. FeGa3 has recently been predicted to become metallic under pressure [1].
We will report on the preliminary results for this project. In particular, we will show how FeGa3 single crystals has been synthesized by the self flux method, and then characterized by means of x-ray diffraction, energy dispersive analysis and MES. Furthermore, our measurements of the magnetic state of FeGa3 as a function of temperature using MES will provide insights not previously reported. Our planned measurements as a function of pressure to search for a proposed metal-insulator transition will also be discussed.

[1] J.M. Osorio-Guillen et al., Phys. Rev. B, 86 (2012) 235202
[2] Y. Amagai et al., J. Appl. Phys., 96 (2004) 5644
[3] Y. Imai and A. Watanabe, Intermetallics, 14 (2006) 722
[4] N. Tsujii et al., J. Phys. Soc. Jpn., 77 (2008) 024705
[5] U. Haussermann et al., J. Solid State Chem., 165 (2002) 94
[6] Y. Hadano et al., J. Phys. Soc. Jpn., 78 (2009) 013702
[7] E.M. Bittar et al., J. Phys. Conf. Ser., 200 (2010) 012014

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 B.P. Doyle, bpdoyle@uj.ac.za, UJ

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

Yes

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

MSc

Primary author

Mr Mustafa Ahmed (University of Johannesburg)

Co-authors

Dr Bryan Doyle (University of Johannesburg) Dr Emanuela Carleschi (University of Johannesburg) Prof. GIOvanni Hearne (University of Johannesburg) Dr Jasper Snyman (University of Johannesburg)

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