Speaker
Mr
Michael Olawale Ogunbunmi
(University of Johannesburg)
Description
We have investigated the ground state properties of the orthorhombic structure compound PrRu2Ga8 which was first announced by the group of Jeitschko [1]. The compound crystallizes in the CaCo2Al8-type structure, belonging to space group Pbam (No. 55). Specific heat data shows a λ-type anomaly at TN = 3.3 K, indicating a bulk phase transition probably of antiferromagnetic nature. At the Neel temperature, TN the entropy approaches the value of 4.66 J/mol.K which is about 0.8Rln2, where R is the universal gas constant. The dc magnetic susceptibility, χ(T) confirms the anomaly at 3.3 K while 1/χ(T) follows the Curie-Weiss law down to low temperatures, with the calculated effective magnetic moment, μeff = 3.47(2) μB and paramagnetic temperature, θp = −7.8(1) K. This magnetic moment value is in good agreement with the Hund’s rule theoretical value of 3.58 μB for a free Pr3+ ion. The electrical resistivity data also show an anomaly at TN and follows a metallic behavior at high temperatures. The Pr3+ in this structure type has a site symmetry of Cs which predicts a crystal electric field (CEF) splitting of the J = 4 multiplet into 9 singlets and thus rule out in principle the occurrence of spontaneous magnetic order. In this work we discuss the magnetic order in PrRu2Ga8 in line with an induced type of magnetism resulting from the admixture of the lowest CEF level with the higher ones [2].
Apply to be<br> considered for a student <br> award (Yes / No)?
Yes
Level for award<br> (Hons, MSc, <br> PhD, N/A)?
PhD
Main supervisor (name and email)<br>and his / her institution
Prof. A.M. Strydom, amstrydom@uj.ac.za
University of Johannesburg
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
Yes
Summary
Keywords: Induced magnetism, Pr-magnetism, crystal electric field
Primary author
Mr
Michael Olawale Ogunbunmi
(University of Johannesburg)
Co-authors
Prof.
Andre Strydom
(University of Johannesburg)
Dr
Buyi Sondezi
(University of Johannesburg)
