7-11 July 2014
Africa/Johannesburg timezone
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Probing the antiferromagnetism in (Cr84Re16)100-yVy alloys using neutron diffraction

Presented by Mrs. Bincy Susan JACOBS on 9 Jul 2014 from 17:10 to 19:00
Type: Poster Presentation
Session: Poster2
Track: Track A - Division for Physics of Condensed Matter and Materials
Board #: A.74

Abstract

Sommerfeld coefficient (<i>γ</i>), obtained from fitting the low temperature specific heat (<i>C</i><sub>p</sub>) data to the equation <i>C</i><sub>p</sub> = <i>γT</i>+ <i>βT</i><sup>3</sup>, has previously been used to identify the region of critical concentration in Cr<sub>1-<i>x</i></sub>V<sub><i>x</i></sub> [1] and in (Cr<sub>84</sub>Re<sub>16</sub>)<sub>100-<i>y</i></sub>V<sub><i>y</i></sub> [2] alloys. The effects of spin fluctuations and nature of the nesting bands on physical properties of Cr<sub>1-<i>x</i></sub>V<sub><i>x</i></sub> alloys were explored using specific heat measurements and the corresponding trends in the <i>γ</i> – <i>x</i> curve [1]. In the (Cr<sub>84</sub>Re<sub>16</sub>)<sub>100-<i>y</i></sub>V<sub><i>y</i></sub>alloy system, <i>γ</i> shows anomalous trends close to the critical concentration as well as at <i>y</i> ≈ 4 [2]. The decrease in <i>γ</i> observed at <i>y</i> ≈ 4 may correspond to the transition from one magnetic phase to another. At <i>y</i> = 0, the alloy system is expected to be in the commensurate spin-density-wave (CSDW) phase [3]. On increasing the V concentration, the incommensurate (I) SDW phase may prevail due to the mismatch between the electron and hole sheets. In order to clarify this conjecture, neutron diffraction studies are proposed. Neutron diffraction is an ideal tool to explore the magnetic phases in an alloy and was successfully used in the Cr<sub>1-<i>x</i></sub>Ru<sub><i>x</i></sub> system to establish the types of antiferromagnetic order in the system [4]. This paper reports on the preliminary results of neutron diffraction on the (Cr<sub>84</sub>Re<sub>16</sub>)<sub>100-<i>y</i></sub>V<sub><i>y</i></sub> alloy system, with <i>y</i> = 0, 4.2 and 6.2. Results indicate that at room temperature, the Cr<sub>84</sub>Re<sub>16</sub> alloy is in the CSDW phase. Possible magnetic satellites indicative of the ISDW phase were observed in the alloys with <i>y</i> = 4.2 and 6.2 as envisaged. [1] Takeuchi J <i>et al</i>., <i>J. Phys. Soc. Japan</i> <b>49</b>, 508 (1980) [2] Jacobs B S <i>et al</i>., <i>J. Appl. Phys.</i> <b>113</b>, 17E126 (2013) [3] Fawcett E <i>et al</i>., <i>Rev. Mod. Phys.</i> <b>66</b> 25 (1994) [4] Papoular R <i>et al</i>., <i>J. Magn. Magn. Mater.</i><b>24</b> 106-110 (1981)

Award

Yes

Level

PhD

Supervisor

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

Paper

Yes

Place

Room: D Ring ground level


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