Prof. Buyi Sondezi

Overview

Field of Specialisation : Material Science, Condensed Matter Physics, Solid State Physics Rare-Earth-Based Oxides and Nanomaterials Group (REBO-NANO Group) Research Interests : From a background of extensive study in the field of highly correlated materials investigated from bulk compounds and alloys, a new frontier into rare-earth-based oxides and nanomaterials is explored. In the studies of the highly correlated matter, great emphasis was put on the behaviour of the rare earth element which is mostly derived from the local moment of the f-electrons, which were observed to be species that were mostly responsible for the behaviour of the whole compound. Materials were studied under extreme conditions; high applied magnetic fields, extremely low temperatures (as low as 50 mK) as well as chemical pressures. All these were done to investigate the stability of the ordering temperature which indicated if the systems could be driven to quantum criticality. Success was achieved from ferromagnetically ordered materials using chemical pressure, where a non-magnetic element was systematically substituted into the well-ordered polycrystalline material. Extending from this knowledge, the behaviour of the rare earth element is further investigated in oxide materials, which form pyrochlores, perovskites and double perovskite materials. These are dependent on the stoichiometry and the synthesis profile employed to get to the desired material. These classes of materials (thin films and nanomaterials) have various possible applications, ranging from energy storage devices, data storage devices, and radiation shielding as well as applications in the medical field. Research projects in this group leverage the strengths and the advantages of the rare-earth element to achieve most of the desired results and subsequent applications. Group Members Postdoctoral Candidates Dr Sibusiso Nqayi Dr Redrisse Fobasso-Djoumessi Dr Bharati Bamana Doctoral Students Mr Tinashe Dhliwayo Mr Eugene Sibanda Mr Samson Simelane Mr Yissah Omotosho Mr Emmanuel Magasi Masters students Miss Khethiwe Cele Miss Zandile Mpupa Mr Mfanafuthi Dlamini Masters in Nanoscience Mr Samkelo Bixa Mr Bethuel Selaelo Mr Victor Sokhela Mr Sabelo Ndlela Research Publications 1. Weak ferromagnetic interactions of Sm 2 Fe 2 O 5+δ induced by coupling of the crystal and related lattice vibrations Nqayi, S. , Sondezi, B. Physica B: Condensed Matter , 2024, 695 , 416501. 2. Crystal and thermodynamic properties of Tb 2 Ni 2 X, (X = Al, Ga) Mpupa, Z.Z. , Tchokonte, M.B.T. , Sondezi, B.M. , Kaczorowski, D. , Strydom, A.M. Physica B: Condensed Matter , 2024, 695 , 416525. 3. Complex magnetic ordering in the noncentrosymmetric metal PrCuGe 3 Ogunbunmi, M.O. , Sondezi, B.M. , Strydom, A.M. Physics Letters, Section A: General, Atomic and Solid-State Physics , 2024, 521 , 129743. 4. Sol-gel synthesis and photoluminescent properties of metal oxide-metal oxide coupled nanocomposites Mabuea, B.P. , Kroon, R.E. , Sondezi, B.M. , Ntwaeaborwa, O.M. Physica B: Condensed Matter , 2024, 675 , 415600. 5. Critical behavior approaches to 3D-Mean field model of GdPdIn Sondezi, B.M. , Altayeb, A. , Tchokonte, M.B.T. , Strydom, A.M. , Sahu, B. Journal of Magnetism and Magnetic Materials , 2024, 589 , 171302. 6. Large magnetocaloric effect in a ternary Laves phase compoundHo 2 Rh 3 Ge Sahu, B. , Xhakaza, S.P. , Sondezi, B.M. , Strydom, A.M. Intermetallics , 2024, 164 , 108058. 7. Large magnetocaloric effect in Ho 2 Pd 2 Pb Sahu, B. , Fobasso, R.D. , Sondezi, B.M. , Strydom, A.M. Materials Today Communications , 2022, 31 , 103327. 8. Rare-earth pyrocoboltates R 2 Co 2 O 7 (R = Ce, Yb): Effective spin-[Formula presented] antiferromagnetic insulators with strong geometrical frustration Ogunbunmi, M.O. , Sondezi, B.M. , Strydom, A.M. Journal of Magnetism and Magnetic Materials , 2021, 535 , 168048. 9. Critical behavior in Nd 2 Pt 2 In studied using the magnetocaloric effect: Comparison with the conventional method Mboukam, J.J. , Tchoula Tchokonté, M.B. , Bashir, A.K.H. , ... Strydom, A.M. , Kaczorowski, D. Materials Research Bulletin , 2020, 122 , 110604. 10. Large magnetocaloric effect in RE 8 Pd 24 Ga (RE = Gd, Tb and Dy) series of compounds Mboukam, J.J. , Tchoula Tchokonté, M.B. , Bashir, A.K.H. , ... Strydom, A.M. , Kaczorowski, D. Journal of Alloys and Compounds , 2020, 814 , 152228. Publication Links: Scopus Google Scholar ORCID