Speaker
Mr
Jean Jules Mboukam
(University of the Western Cape)
Description
The ferromagnet Nd2Pt2In compound was investigated by means of electrical resistivity, &rho(T), magnetic susceptibility, &chi(T), magnetization, M(µ0H), heat capacity, Cp(T) and magnetocaloric effect (MCE). Powder X – ray diffraction results confirm the tetragonal Mo2FeB2 – type crystal structure with space group P4/mbm (No. 127). At high temperatures, &rho(T) data shows metallic behaviour with a downward curvature and that is described by the Bloch – Gruneissen – Mott’s relation. At low temperature, &rho(T) data shows an anomaly associated with ferromagnetism phase transition at TC = 18 K. Below TC, &rho(T) is well described by a spin – wave dispersion with energy gap, &Delta = 15.7(9) K. &chi(T) data at high temperatures follows the Curie – Weiss relationship given and effective magnetic moment value, µeff = 3.61(2) µB and the Weiss temperature constant &thetap = 16(1) K. The observed µeff value is close to the value of 3.62 µB expected for the Nd3+ - ion. At low temperatures, &chi(T) data exhibit a sharp rise characteristic of ferromagnetic (FM) materials. TC was estimated at the minimum of d&chi(T)/dT curve at TC = 17.8 K, which is close to the value of 18 K observed in &rho(T) data. Cp(T) data confirms the FM phase transition at TC = 17.9 K taken at the midpoint of the maximum slope of the &lambda - type anomaly and close to the values of 18 K and 17.8 K observed in 7rho(T) and &chi(T) data respectively. The 4f – electron specific heat C4f(T), indicates a Schottky – type anomaly at high temperatures associated with crystalline – electric – field (CEF). The Arrott – plot indicate a second – order FM phase transition. The MCE estimated from the magnetization data gives value of 6.25 J/kg.K for a field change of 7T. The isothermal magnetic entropy change maximum (&Delta SMmax) follows a linear behaviour with h2/3 (h being the reduced field) with a negative y – intercept, which confirms the mean – field theory for a send – order phase transition.
Level for award<br> (Hons, MSc, <br> PhD, N/A)?
MSc
Apply to be<br> considered for a student <br> award (Yes / No)?
Yes
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
No
Main supervisor (name and email)<br>and his / her institution
Prof. Moise Tchoula Tchokonte, University of the Western Cape
mtchokonte@uwc.ac.za
Primary author
Mr
Jean Jules Mboukam
(University of the Western Cape)
Co-authors
Mr
Amal Bashir
(University of the Western Cape)
Prof.
Andre Strydom
(University of Johannesburg)
Dr
Buyisiwe Sondezi
(University of Johannesburg)
Prof.
Dariusz Kaczorowski
(Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland)
Prof.
Moise Bertin Tchoula Tchokonte
(Department of Physics, University of the Western Cape)
Dr
Ramesh Kumar
(University of Johannesburg)
