9-13 July 2012
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=11&confId=14"><font color=#ff0000>SAIP2012 PROCEEDINGS AVAILABLE</font></a>

Spin density wave behaviour in the (Cr<sub>84</sub>Re<sub>16</sub>)<sub>100-y</sub>V<sub>y</sub> system

11 Jul 2012, 08:40
20m
Oral Presentation Track A - Division for Condensed Matter Physics and Materials DCMPM2

Speaker

Mrs Bincy Susan Jacobs (University Of Johannesburg)

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

Yes

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

Prof 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

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

PhD

Abstract content <br> &nbsp; (Max 300 words)

The spin density wave (SDW) behaviour in the (Cr84Re16)100-yVy alloy system, with 4 ≤ y ≤ 14, was investigated using electrical resistivity (ρ), Seebeck coefficient (S) and specific heat (Cp) measurements as a function of temperature (T). For this alloy series ρ measurements reveal a clear anomaly at the Néel temperature (TN), which can be ascribed to the opening up of the SDW energy gap and the corresponding decrease in charge carrier density on cooling through TN [1]. The Seebeck coefficient is sensitive to the changes in the electronic structure and scattering mechanisms that are consequential to the antiferromagnetic phase [1]. An anomaly in the form of a hump in the vicinity of TN is observed in the S(T) curves for samples with y = 5.7 and 8.5. On increasing y the magnitude of this anomaly is suppressed and the position of the hump shifts to lower temperatures, corresponding to a decrease in TN. At low temperatures, a broad valley is observed for y = 4 and 5.7. On increasing y, this valley initially becomes more pronounced, but eventually weakens and becomes imperceptible in samples with y > 5.7. TN(y) obtained from both ρ(T) and S(T) measurements indicate the existence of a possible quantum critical point at y ≈ 10.4. Signatures of quantum critical behaviour have also been linked to anomalies in the behaviour of the Sommerfeld electronic specific heat coefficient (γ) as a function of the tuning parameter [2]. γ is obtained from the low temperature Cp measurements and γ(y) for the (Cr84Re16)100-yVy alloy system also shows an anomaly in the vicinity of the putative quantum critical point.

[1] E. Fawcett et al., Rev. Mod. Phys. 66, 25 (1994).
[2] J. Takeuchi et al., J. Phys. Soc. Jpn. 49, 508 (1980)

Primary author

Mrs Bincy Susan Jacobs (University Of Johannesburg)

Co-authors

Prof. Aletta Prinsloo (University Of Johannesburg) Prof. Andre Strydom (University Of Johannesburg) Dr Charles Sheppard (University Of Johannesburg)

Presentation Materials

Peer reviewing

Paper