Prof. Giovanni Hearne

Professor
Name: Giovanni Hearne
Location: C1 Lab 129 Auckland Park Kingsway Campus
Physics Academic Staff  Staff Members

Contact Details:
Tel: 011 559 3849

Email: grhearne@uj.ac.za

About Prof. Giovanni Hearne

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

1. “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)
2. “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)
3. “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)
4. “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)
5. “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)
6. “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
7. “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 )
8. “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
9. “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)
10. “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)
11. “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)
12. “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)
13. “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)
14. “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
15. “(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

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ORCID ID: 0000-0002-1662-7831