Prof. Giovanni Hearne

Overview

Fields of Specialisation: Materials Science, Solid State Physics Condensed Matter, Physics. NRF rating: B2 Research interests Experimental Condensed Matter Physics. 57Fe Mössbauer-effect spectroscopy at variable cryogenic temperatures (down to 1.5 K) and high pressures (up to one megabar). High pressure physics (diamond- and gem- anvil cells, DACs and GACs). Laser spectroscopy, XRD, electrical-transport and synchrotron-based techniques (XAS), at high pressures. CO2 laser heating in DACs. Lattice-dynamics, superconductivity, magnetism , magnetic-electronic (insulator-metal and spin-state) transitions (in strongly correlated electron systems SCES), materials science. Instrumentation physics (electronics). Participation in numerous research projects pertaining to applied, industrial and bio-molecular physics. 197Au (gold) Mössbauer-effect spectroscopy. For information on Prof G. Hearne's research interest, please click on this link . Recent Research outputs “Interplay between H-bonding proton dynamics and Fe valence fluctuations in Fe3(PO4)2(OH)2 at high pressure” G. Hearne , V. Ranieri, P. Hermet, J. Haines, O. Cambon, J.L. Bantignies, P. Fertey, T. Stuerzer, M. Poienar, J. Rouquette Phys. Rev. B 107, (2023) L060302 (1-8) “Effects of light-ion low-fluence implantation on the pressure response of double-walled carbon nanotubes” G. R. Hearne , L. Kapesi, R. M. Erasmus, S. R. Naidoo, and R. Warmbier Phys. Rev. Materials 5, (2021), 033607 (1-11) “Pressure-Induced Spin Crossover at Room Temperature in a Nanoporous Host-Guest Framework Structure” Banele Vatsha, Rowan Goliath, and Giovanni Hearne ChemPlusChem 86, (2021), 82–86 Also selected as a Cover Feature (CHEMPLUSCHEM 1/21) (see https://0-doi-org.ujlink.uj.ac.za/10.1002/cplu.202000705) “Interplay between valence fluctuations and lattice instabilities across the quantum phase transition in EuCu2(Ge1-xSix)2 ” Mahmoud A. Ahmida, Dirk Johrendt, Giovanni R. Hearne , Christoph Geibel, Zakir Hossain, and Mohsen M. Abd-Elmeguid Phys. Rev. B 102, (2020) 155110 (1-13) “Charge fluctuations across the pressure–induced quantum phase transition in EuCu2(Ge1−xSix)2” Mahmoud A. Ahmida, Martin K. Forthaus, Christoph Geibel, Zakir Hossain, Giovanni R. Hearne , Jirka Kaštil, Jiri Prchal, Vladimir Sechovský, and Mohsen M. Abd-Elmeguid Phys. Rev. B 101, (2020) 205127 (1-10) “Unusual pressure-induced metallic state in the correlated narrow band-gap semiconductor FeSi” G. R. Hearne , P. Musyimi, S. Bhattacharjee, M.K. Forthaus and M.M. Abd-Elmeguid. Phys. Rev. B 100, (2019) 155118 (1-9). Highlighted as Editors’ Suggestion “Pressure-induced disruption of the local environment of Fe-Fe dimers in FeGa3 accompanied by metallization” G. R. Hearne , S. Bhattacharjee, B. P. Doyle, M. A. M. Ahmed, P. Musyimi, E. Carleschi and B. Joseph. Phys. Rev. B 98, (2018) 020101(R) (1-5) Also featured in Elettra Highlights 2018-2019 (see https://www.elettra.eu/images/Documents/SCIENCE/Elettra%20HL%202019.pdf ) “Electron-density distributions in selected ferrocenyl-pyrazolyl late transition metal complexes” M. A. Peck, G. R. Hearne , C. Obuah and J. Darkwa Phys. Chem. Chem. Phys. 20, (2018) 11682-11691 “Site-specific spin crossover in Fe2TiO4 post-spinel under high pressure up to nearly a megabar” W. M. Xu, G. R. Hearne , S. Layek, D. Levy, J.-P. Itié, M. P. Pasternak, G. Kh Rozenberg, and E. Greenberg Phys. Rev. B 96, (2017) 045108 (1-11) “Interplay between structural and magnetic-electronic responses of FeAl2O4 to a megabar: Site inversion and spin crossover” W. M. Xu, G. R. Hearne , S. Layek, D. Levy, M. P. Pasternak, G. Kh Rozenberg, and E. Greenberg Phys. Rev. B 97, (2018) 085120 (1-9) “FeCr2O4 spinel to near megabar pressures: Orbital moment collapse and site-inversion facilitated spin crossover” W. M. Xu, G. R. Hearne , S. Layek, D. Levy, J.-P. Itié, M. P. Pasternak, G. Kh Rozenberg, and E. Greenberg Phys. Rev. B 95, (2017) 045110 (1-9) “CuFeO2 at a megabar: Stabilization of a mixed-valence low-spin magnetic semiconducting ground state” W. M. Xu, G. R. Hearne , and M. P. Pasternak Phys. Rev. B 94, (2016) 035155 (1-6) “Coexistence of site- and bond-centered electron localization in the high-pressure phase of LuFe2O4” G. R. Hearne , E. Carleschi, W. N. Sibanda, P. Musyimi, G. Diguet, Yu. B. Kudasov, D. A. Maslov, and A. S. Korshunov Phys. Rev. B 93, (2016) 105101 (1-7) “K-edge x-ray dichroism investigation of Fe1-xCoxSi: Experimental evidence for spin polarization crossover” G.R. Hearne , G.Diguet, F.Baudelet , J.-P.Itié , N.Manyala Journal of Magnetism and Magnetic Materials 379 , (2015) 274–279 “(Phenoxyimidazolyl-salicylaldimine) iron complexes: synthesis , properties and iron catalysed ethylene reactions” M. Yankey, C. Obuah, I. A. Guzei, E. Osei-Twum, G. Hearne and J. Darkwa Dalton Trans. 43, (2014), 13913–13923 External Links Google Scholar Research Gate ORCID ID: 0000-0002-1662-7831