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>

Effect of Mo content on the Structural and Physical Properties of Cr<sub>100-<i>x </i></sub>Mo<sub><i>x</i></sub>Alloys

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

D Ring ground level

Board: A.76
Poster Presentation Track A - Division for Physics of Condensed Matter and Materials Poster2

Speaker

Dr A Chavan (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>

Antiferromagnetic order in Cr is attributed to the formation of a spin density wave (SDW) when the electron and hole Fermi sheets overlap on cooling through the Néel temperature (TN). This nesting effect is sensitive to changes in the electron-to-atom (e/a) ratio and is influenced by the diluent materials used with Cr. Alloying with elements to the left of Cr on the periodic table reduces the size of the electron sheet and results in lowering TN with increasing diluent concentration, while elements to the right of Cr have an opposite effect. Considering this, investigations into the physical properties of Cr alloys with isoelectronic elements is important, as it rules out this effect of e/a. Alloying Cr with Mo, which is isoelectric with Cr, shows an unexpected decrease in TN with increasing Mo concentration [1]. This is attributed to the delocalization of the 3-d bands in Cr through the introduction of the 4-d electrons of Mo [1]. In the present investigation the effect of Mo concentration on the structural, magnetic and electrical properties of Cr is systematically studied. A series of Cr100-xMox alloys, with x = 0, 3, 7, 15 and 25, was prepared and the actual concentrations established using electron microprobe analysis. XRD studies confirm the bcc structure of these alloys and indicate an increase in lattice constant with increase in Mo concentration. The crystallite sizes calculated from these results for the Cr100-xMox alloys ranges between 15 to 30 nm. The physical properties of these alloys were investigated through susceptibility (χ), Seebeck coefficient (S), resistivity (ρ) and Hall coefficient (RH) as function of temperature (T) measurements. TN-values obtained from these measurements are comparable. Interestingly, for sample x = 3, χ(T) shows a spin-flip transition at TSF ≈ 65K and RH(T) indicates a change in mobility carriers at T ≈ 100K.

[1] Fawcett E et al. 1994 Rev. Mod. Phys . 66 25.

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

No

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)?

-

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

ARE Prinsloo,
alettap@uj.ac.za,
University of Johannesburg

Primary author

Dr A Chavan (University of Johannesburg)

Co-authors

Dr ARE Prinsloo (University of Johannesburg) Mr Blessed Muchono (University of Johannesburg) Dr C Sheppard (University of Johannesburg)

Presentation Materials

Peer reviewing

Paper