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Physics Superconductivity and Magnetism

Geetha Balakrishnan

Geetha Balakrishnan is a Professor in the Physics Department at the University of Warwick.

She has worked at Warwick since 1991. She has previously worked at the Tata Institute of Fundamental Research in Bombay, India (1989-1991) and also as a Research Fellow in the Physics Department at Warwick (1986-1988).

Research Interests

The growth of single crystals of superconductors, magnetic, and related materials by a variety of techniques, including a large programme of work using optical furnaces for the floating zone technique.

Also low temperature laboratory measurements and neutron scattering studies.

For more details on the research activities of Prof. Geetha Balakrishnan and the other members of the Superconductivity and Magnetism Group please visit our Research Pages.

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Recent research grants:

EP/T005963/1 "Single Crystal Growth at Warwick" Sep 2019-Sep 2023, £634,595 (PI)

EP/N032128/1 “Skyrmionics: From Magnetic Excitations to Functioning Low-Energy Devices” Programme Grant led by Prof. Peter Hatton, Durham, July 2016-Jan 2023, £5,101,385 (Warwick PI)

EP/M028941/1 “Investigations of the physics underlying the principles of design of rare earth transition metal permanent magnets” Jan 2016-Jun 2020, £931,725 (Co-I)

EP/M028771/1 “Single Crystal Growth at Warwick” July 2015- July 2018, EPSRC, UK, £514,769 (PI)

EP/L014963/1 “Topological Insulators: A study of bulk crystalline and nanomaterials
March 2014-Aug 2017, EPSRC, UK, £616, 679 (PI)

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Selected recent publications:

(For a full list of publications please see link at the bottom of the list)

  • Bismuth chalcogenide topological insulators crystals grown by the optical floating zone technique, A. Guarino, R. Arumugam, R. Fittipaldi, M. Lettieri, G. Balakrishnan, A. Vecchione,

    Journal of Crystal Growth 629, 127580 (2024).

  • Crystal growth and Hall effect of the non-centrosymmetric superconductor α-BiPd and the topological superconductor β-Bi2Pd, R. Arumugam, R. Fittipaldi, A. Guarino, D. Mayoh, A. Ubaldini, M. Lettieri, G. Avallone, A. Romano, G. Balakrishnan, A. Vecchione,

    Journal of Crystal Growth 630, 127592 (2024).

  • Valence-state mixing and reduced magnetic moment in Fe3-δGeTe2 single crystals with varying Fe content probed by x-ray spectroscopy, D. Backes, R. Fujita, L. S. Veiga, D. A. Mayoh, G. D. A. Wood, S. S. Dhesi, G. Balakrishnan, G. van der Laan, T. Hesjedal, Nanotechnology 35, 395709 (2024).
  • Chemical Trends of the Bulk and Surface Termination-Dependent Electronic Structure of Metal-Intercalated Transition Metal Dichalcogenides, B. Edwards, D. A. Deaconu, P. A. E. Murgatroyd, S. Buchberger, T. Antonelli, D. Halliday, G. R. Siemann, A. Zivanovic, L. Trzaska, A. Rajan, E. A. Morales, D. A. Mayoh, A. E. Hall, R. V. Belosludov, M. D. Watson, T. K. Kim, D. Biswas, T. L. Lee, C. M. Polley, D. Carbone, M. Leandersson, G. Balakrishnan, M. S. Bahramy, P. D. C. King,

    Chemistry of Materials DOI 10.1021/acs.chemmater.4c00824 (2024).

  • Magnetic structure, excitations, and field-induced transitions in the honeycomb lattice compound Er2Si2O7, M. Islam, N. d'Ambrumenil, D. D. Khalyavin, P. Manuel, F. Orlandi, J. Ollivier, M. C. Hatnean, G. Balakrishnan, O. A. Petrenko, Physical Review B 109, 094420 (2024).
  • Strain-Modulated Ferromagnetism at an Intrinsic van der Waals Heterojunction R. Fujita, G. Gurung, M. A. Mawass, A. Smekhova, F. Kronast, A. K. J. Toh, A. Soumyanarayanan, P. Ho, A. Singh, E. Heppell, D. Backes, F. Maccherozzi, K. Watanabe, T. Taniguchi, D. A. Mayoh, G. Balakrishnan, G. van der Laan, T. Hesjedal, Advanced Functional Materials DOI 10.1002/adfm.202400552 (2024).
  • Quantum critical behaviour of the hyperkagome magnet Mn3CoSi, H. Yamauchi, D.P. Sari, Y. Yasui, T. Sakakura, H. Kimura, A. Nakao, T. Ohhara, T. Honda, K. Kodama, N. Igawa, K. Ikeda, K. Iida, D. Ueta, T. Yokoo, M.D. Frontzek, SX. Chi, J.A. Fernandez-Baca, K.M. Kojima, D. Arseneau, G. Morris, B. Hitti, Y.P. Cai, A. Berlie, I. Watanabe, P.T. Hsu, Y.S. Chen, M.K. Lee, A.E. Hall, G. Balakrishnan, L.J. Chang, S. Shamoto. Physical Review Research 6 (1) 013144 (2024)
  • Control of stripe, skyrmion and skyrmionium formation in the 2D magnet Fe3-xGeTe2 by varying composition.M.T. Birch, L. Powalla, K. Litzius, V. Nehruji, O. Hovorka, S. Wintz, F. Schulz, D.A. Mayoh, G. Balakrishnan, M. Wiegand, M. Burghard, G.Schutz.2D Materials 11 (2) 025008 (2024).
  • Flux-pinning mediated superconducting diode effect in NbSe2/CrGeTe3 heterostructure, Mehrnejat A, M.C. Hatnean M.C. Rosamond, N. Banerjee, G. Balakrishnan, S.E. Savelev, F.K. Dejene. 2D Materials 11 (2) 021002 (2024)

  • Giant valley Zeeman coupling in the surface layer of an intercalated transition metal dichalcogenide B. Edwards, O. Dowinton, A.E. Hall, P.A.E.Murgatroyd, S. Buchberger, T. Antonelli, G.-R. Siemann, A. Rajan, E. Abarca Morales, A. Zivanovic, C. Bigi, R.V. Belosludov, C.M. Polley, D. Carbone, D.A. Mayoh, G. Balakrishnan, M.S. Bahramy, and P.D.C. King, Nature Materials, (2023)

  • Comparative study of the magnetism in Mn3RhGe and related compound Mn3IrSi, A. E. Hall, P. Manuel, D. D. Khalyavin, F. Orlandi, D. A. Mayoh, L. J. Chang, Y. S. Chen, D. G. C. Jonas, M. R. Lees, G. Balakrishnan, Physical Review Materials 7, 114402 (2023).
  • Covalency, correlations, and interlayer interactions governing the magnetic and electronic structure of Mn3Si2Te6. Bigi, L Qiao, C. Liu, P. Barone, M.C. Hatnean, G.R. Siemann, B. Achinuq, D.A. Mayoh, G. Vinai, V. Polewczyk, D. dagur, F. Mazzola, P. bencok, T. Hesjedal, G. Van der Laan, W. Ren, G. Balakrishnan, S. Picozzi, P.D.C.King. Physical Review B 108 (5) 054419 (2023)
  • Hydrogen-impurity-induced unconventional magnetism in semiconducting molybdenum ditelluride, J. A. Krieger, D. Tay, I. P. Rusinov, S. Barua, P. K. Biswas, L. Korosec, T. Prokscha, T. Schmitt, N. B. M. Schröter, T. Shang, T. Shiroka, A. Suter, G. Balakrishnan, E. Chulkov, V. N. Strocov, Z. Salman, Physical Review Materials 7, 044414 (2023).

  • X-ray holographic imaging of magnetic surface spirals in FeGe lamellae L. A. Turnbull, M. T. Littlehales, M. N. Wilson, M. T. Birch, H. Popescu, N. Jaouen, J. A. T. Verezhak, G. Balakrishnan, P. D. Hatton Physical Review B 2022-08-15

  • Magnetism in the Néel-skyrmion host GaV4S8 under pressure T. J. Hicken, M. N. Wilson, S. J. R. Holt, R. Khassanov, M. R. Lees, R. Gupta, D. Das, G. Balakrishnan, T. Lancaster Physical Review B 2022-04-13

  • Singlet-triplet mixing in the order parameter of the noncentrosymmetric superconductor Ru7B3 A. S. Cameron, Y. S. Yerin, Y. V. Tymoshenko, P. Y. Portnichenko, A. S. Sukhanov, M. Ciomaga Hatnean, D. McK. Paul, G. Balakrishnan, R. Cubitt, A. Heinemann Physical Review B 2022-03-29

  • Comparative study of the structural and magnetic properties of Mn1/3NbS2 and Cr1/3NbS2 A. E. Hall, J. C. Loudon, P. A. Midgley, A. C. Twitchett-Harrison, S. J. R. Holt, D. A. Mayoh, J. P. Tidey, Y. Han, M. R. Lees, G. Balakrishnan Physical Review Materials 2022-02-23

  • Frustrated Magnet Mn3Al2Ge3O12 Garnet: Crystal Growth by the Optical Floating Zone Method, M. Islam, M. C. Hatnean, G. Balakrishnan, O. A. Petrenko, Crystals 13, 397 (2023).
  • Giant topological and planar Hall effect in Cr1/3NbS2 D. A. Mayoh, J. Bouaziz, A. E. Hall, J. B. Staunton, M. R. Lees, G. Balakrishnan Physical Review Research 2022-02-18
  • Toggle-like current-induced Bloch point dynamics of 3D skyrmion strings in a room temperature nanowire M. T. Birch, D. Cortés-Ortuño, K. Litzius, S. Wintz, F. Schulz, M. Weigand, A. Štefančič, D. A. Mayoh, G. Balakrishnan, P. D. Hatton Nature Communications 2022-06-24
  • Investigations of the size distribution and magnetic properties of nanoparticles of Cu2OSeO3 S J R Holt, A Štefančič, J C Loudon, M R Lees, G Balakrishnan Materials Research Express 2021-11-01
  • Absence of zero-field-cooled exchange bias effect in single crystalline La2−xAx CoMnO6 (A=Ca,Sr) compounds C. Macchiutti, J. R. Jesus, F. B. Carneiro, L. Bufaiçal, M. Ciomaga Hatnean, G. Balakrishnan, E. M. Bittar Physical Review Materials 2021-09-07
  • Emergent magnetic behavior in the frustrated Yb3Ga5O12 garnet Lise Ørduk Sandberg, Richard Edberg, Ingrid-Marie Berg Bakke, Kasper S. Pedersen, Monica Ciomaga Hatnean, Geetha Balakrishnan, Lucile Mangin-Thro, Andrew Wildes, B. Fåk, Georg Ehlers Physical Review B 2021-08-13
  • Field-temperature phase diagram of the enigmatic Nd2(Zr1−xTix)2O7 pyrochlore magnets M. Léger, E. Lhotel, E. Ressouche, K. Beauvois, F. Damay, C. Paulsen, A. Al-Mawla, E. Suard, M. Ciomaga Hatnean, G. Balakrishnan Physical Review B 2021-06-28
  • Magnetic structure investigation of the intercalated transition metal dichalcogenide V1/3NbS2 A. E. Hall, D. D. Khalyavin, P. Manuel, D. A. Mayoh, F. Orlandi, O. A. Petrenko, M. R. Lees, G. Balakrishnan Physical Review B 2021-05-25
  • Superconducting quantum interference in twisted van der Waals heterostructures Farrar LS, Nevil A, Lim ZJ, Balakrishnan G, Dale S and Bending S J, Nano Letters 21 6725 (2021)
  • Topological defect-mediated skyrmion annihilation in three dimensions M. T. Birch, D. Cortés-Ortuño, N. D. Khanh, S. Seki, A. Štefančič, G. Balakrishnan, Y. Tokura, and P. D. Hatton, Communications Physics 4, 175 (2021)
  • Deriving the skyrmion Hall angle from skyrmion lattice dynamics. S. R. Brearton, L. A. Turnbull, J. A. T. Verezhak, G. Balakrishnan, P. D. Hatton, G. van der Laan, and T. Hesjedal. Nature Communications 12, 2723 (2021)
  • Chiral singlet superconductivity in the weakly correlated metal LaPt3P P. K. Biswas, S. K. Ghosh, J. Z. Zhao, D. A. Mayoh, N. D. Zhigadlo, X. Xu, C. Baines, A. D. Hillier, G. Balakrishnan, and M. R. Lees. Nature Communications 12, 2504 (2021)
  • Magnetic structure investigation of the intercalated transition metal dichalcogenide V1/3NbS2 A. E. Hall, D. D. Khalyavin, P. Manuel, D. A. Mayoh, F. Orlandi, O. A. Petrenko, M. R. Lees, and G. Balakrishnan. Physical Review B 103, 174431 (2021).
  • Megahertz dynamics in skyrmion systems probed with muon-spin relaxation. T. J. Hicken, M. N. Wilson, K. J. A. Franke, B. M. Huddart, Z. Hawkhead, M. Gomilšek, S. J. Clark, F. L. Pratt, A. Štefančič, A. E. Hall, M. Ciomaga Hatnean, G. Balakrishnan, and T. Lancaster. Physical Review B 103, 024428 (2021).
  • Investigation of the magnetic ground state of GaV4S8 using powder neutron diffraction S. J. R. Holt, C. Ritter, M. R. Lees, and G. Balakrishnan. Journal of Physics: Condensed Matter 33 255802 (2021).
  • Spin Dynamics and Unconventional Coulomb Phase in Nd2Zr2O7 M. Léger, E. Lhotel, M. Ciomaga Hatnean, J. Ollivier, A. R. Wildes, S. Raymond, E. Ressouche, G. Balakrishnan, and S. Petit. Physical Review Letters 126, 247201 (2021).
  • Evidence for the coexistence of time-reversal symmetry breaking and Bardeen-Cooper-Schrieffer-like superconductivity in La7Pd3 D. A. Mayoh, A. D. Hillier, G. Balakrishnan, and M. R. Lees.  Physical Review B 103, 024507 (2021).

  • Tilted X-Ray Holography of Magnetic Bubbles in MnNiGa Lamellae. L. A. Turnbull, M. T. Birch, A. Laurenson, N. Bukin, E. O. Burgos-Parra, H. Popescu, M. N. Wilson, A. Stefancic, G. Balakrishnan, F. Y. Ogrin, and P. D. Hatton. ACS Nano 15, 387-395 (2021)

  • Real-space imaging of confined magnetic skyrmion tubes, M. T. Birch, D. Cortés-Ortuño, L. A. Turnbull, M. N. Wilson, F. Groß, N. Träger, A. Laurenson, N. Bukin, S. H. Moody, M. Weigand, G. Schütz, H. Popescu, R. Fan, P. Steadman, J. A. T. Verezhak, G. Balakrishnan, J. C. Loudon, A. C. Twitchett-Harrison, O. Hovorka, H. Fangohr, F. Y. Ogrin, J. Gräfe, and P. D. Hatton, Nature Communications 11, 1726 (2020)

  • Crystal Growth by the Floating Zone Method of Ce-Substituted Crystals of the Topological Kondo Insulator SmB6, M. Ciomaga Hatnean, T. Ahmad, M. Walker, M.R. Lees, and G. Balakrishnan. Crystals 10, 827 (2020)

  • Optical Floating Zone Crystal Growth of Rare-Earth Disilicates, R2Si2O7 (R = Er, Ho, and Tm), M. Ciomaga Hatnean, O.A. Petrenko, M.R. Lees, T.E. Orton, and G. Balakrishnan. Crystal Growth and Design 20, 6636-6648 (2020).

  • Structure and magnetism of the skyrmion hosting family GaV4S8-ySey with low levels of substitutions between 0 ≤ y ≤ 0.5 and 7.5 ≤ y ≤ 8. S.J.R. Holt, A. Štefančič, C. Ritter, A.E. Hall, M.R. Lees, and G. Balakrishnan. Physical Review Materials 4, 114413 (2020)

  • Intrinsic Bulk Quantum Oscillations in a Bulk Unconventional Insulator SmB6 M. Hartstein, H. Liu, Y. T. Hsu, B. S. Tan, M. C. Hatnean, G. Balakrishnan, S. E. Sebastian. Iscience 23, 101632 (2020).

  • Direct observation of the energy gain underpinning ferromagnetic superexchange in the electronic structure of CrGeTe3. MD Watson, I Markovic, F Mazzola, A Rajan, EA Morales, DM Burn, T Hesjedal, G van der Laan, S Mukherjee, TK Kim, C Bigi, I Vobornik, M Ciomaga Hatnean, G Balakrishnan, PDC King. Phys. Rev. B 101 205125 (2020)
  •  Real-space imaging of confined magnetic skyrmion tubes. MT Birch, D Cortes-Ortuno, LA Turnbull, MN Wilson, F Gross, N Trager, A Laurenson, N Bukin, SH Moody, M Weigand, G Schutz, H Popescu, R Fan, P Steadman, JAT Verezhak, G Balakrishnan, JC Loudon, AC Twitchett-Harrison, O Hovorka, H Fangohr, FY Grin, J Grafe, PD Hatton. Nature Commun. 11 1726 (2020).

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Orcid full publications list:

https://orcid.org/0000-0002-5890-1149

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Full list of publications: Please click on "Researcher ID" to view the list

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Write to

Department of Physics
University of Warwick
Coventry CV4 7AL
United Kingdom

Contact Details

Office
P236
Telephone
+44 (0)2476573879
E-Mail
G.Balakrishnan(at)warwick.ac.uk