Speaker
Level for award<br> (Hons, MSc, <br> PhD)?
PhD
Apply to be<br> considered for a student <br> award (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>
An investigation of the physical properties of Cr100-xIrx alloy single crystals, with x = 0.7, 1.5, 2.0 and 2.5, were previously used to establish the magnetic phase diagram of Cr100-xIrx alloy system around triple point concentration [1] where the various magnetic phases co-exist. The present study extends these results by considering the temperature (T) dependence of the Seebeck coefficient (S), specific heat (Cp) and Hall coefficient (RH) measurements, in addition to the electrical resistivity (ρ) [1]. Well defined anomalies were observed in the electrical resistivity ρ(T) curves of all the samples, due to the antiferromagnetic to paramagnetic phase transition on heating through the Néel temperature (TN). The S(T) curves of the samples with x = 0.7, 1.5 and 2.0 also exhibit anomalies associated with TN in the temperature range below 380 K. As the upper limit of temperature for the measurements was 380 K, the anomaly associated with TN could not be observed for x = 2.5 alloy (TN = 391.5 K). Contrary to what is normally expected [2] it is noted that the anomaly related to TN is more prominent in the (ρ) curves than in the S(T) curves. (RH) measurements carried out from 380 K down to 2 K in a constant magnetic field of 6 T, shows only weak anomalies at TN for certain samples. The Sommerfeld coefficient (γ) is obtained by fitting Cp/T = γ + (β)T2 to the low temperature Cp/T versus T2 data. The γ values found for the present single crystal samples fits in well with the γ versus electron-to-atom (e/a) ratio curve previously published [3, 4] for certain Cr alloys.
[1].Martynova J et al. 1998 J. Magn. Magn. Mat 187 345
[2].Fawcett E et al.1994 Rev. Mod. Phys. 66 25
[3].Heiniger F 1966 Phys. Kondens. Materie 5 285
[4].Heiniger F et al. 1966 Phys. Kondens. Materie 5 243
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
Yes
Main supervisor (name and email)<br>and his / her institution
ARE Prinsloo
alettap@uj.ac.za
