Speaker
Apply to be<br> considered for a student <br> award (Yes / No)?
yes
Abstract content <br> (Max 300 words)
The magnetic phase diagram of Cr100-x Osx exhibits a triple point at TL = 315 K and xL = 0.14,where the incommensurate (I) spin-density-wave (SDW),commensurate (C) SDW and paramagnetic (P) phases coexist. Previous studies [1,2] focused on measurements around the triple point and concentrations up to x = 2. However, the magnetic phase diagrams [1] of other Cr alloys with group-8 diluents, such as those of Cr-Re and Cr-Ru, show interesting features for x >> xL.This is indicative of the possible merits of an investigation into the magnetic phase diagram of Cr-Os,specifically at high diluent concentrations. For this purpose, a polycrystalline Cr100-xOsx alloy series with 2 < x < 22 was prepared. Sample buttons were arc-melted from high quality starting materials and characterized using scanning electron microscopy, electron microprobe analysis and X-ray diffraction. Analyses show that the alloys are homogenous in composition and single-phase for Os diluent concentration up to x = 22. Electrical resistivity (ρ) measurements as function of temperature (T),in the temperature range of 2 K < T < 1100 K, was used to obtain the magnetic transition temperatures of the various alloys. The onset of antiferromagnetism causes large anomalies in the ρ versus T curves, associated with the Néel transition temperatures (TN)[1]. These results were used to determine the magnetic phase diagram of the Cr100-xOsx alloy system for x > 2. Present results show that TN increases up to 575 K at x = 4, and then decreases for x > 4. This behaviour is similar to that observed for other Cr alloys with group-8 impurities [1].Interestingly, results reveal that the antiferromagnetism in the Cr100-xOsx alloy system is fully suppressed at x = 13. The present results are interpreted and explained in terms of the theory of Fedders and Martin [3].
[1] Fawcett E, Alberts HL, Galkin VY, Noakes DR and Yakhmi JV 1994 Rev. Mod. Phys. 66 25.
[2] Butylenko AK and Nevadcha VV 1982 Sov. Phys. Tech. Phys. 27(1) 102.
[3] Fedders PA and Martin PC 1966 Phys. Rev. 143 245.
Level for award<br> (Hons, MSc, <br> PhD)?
PhD
Main supervisor (name and email)<br>and his / her institution
ARE Prinsloo,
alettap@uj.ac.za,
Department of Physics, University of Johannesburg, PO Box 524, Auckland Park, 2006
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
Yes
