Speaker
Main supervisor (name and email)<br>and his / her institution
ARE Prinsloo,
alettap@uj.ac.za,
University of Johannesburg
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
Yes
Abstract content <br> (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.
Level for award<br> (Hons, MSc, <br> PhD)?
-
Apply to be<br> considered for a student <br> award (Yes / No)?
No
