Starting from June 2018, I am a Senior Research Fellow in the Superconductivity and Magnetism Group.
I initially joined the research group as a Post Doctoral Research Fellow in January 2013 and I have been working jointly with Prof. Geetha Balakrishnan, Prof. Don Paul, Dr. Martin R. Lees and Dr. Oleg A. Petrenko.
I have previously completed a Ph.D. in Chemistry at Paris-Sud University, Orsay, France in 2012, under the joint supervision of Prof. Loreynne Pinsard-Gaudart and Dr. Habil. Sylvain Petit. I worked on the "Synthesis and study of the Ga2-xFexO3 compounds" at LPCES-ICMMO, Orsay and LLB, CEA-Saclay.
Overview of my work
My current project involves the crystal growth and study of single crystals of various compounds (oxides, borides, chalcogenides and intermetallic magnetic and superconducting materials). The materials that I am studying range from multiferroics and frustrated magnets to a variety of newly discovered exotic states of matter (Topological Insulators, Skyrmion lattices).
The investigation of the physics of all the materials that I produce at Warwick requires a range of techniques, including in house magnetic, thermodynamic and transport measurements, as well as the use of central facilities using X-ray diffraction, neutron scattering and muon spectroscopy techniques.
Research interests (highlights) and expertise
- I am actively involved in the study of newly discovered states of matter, such as superconductors, topological insulators and skyrmion lattices. My contributions include growth and characterisation of large high quality single crystals of topological insulators, such as SmB6 and YbB12, preparation and study of crystals of materials which exhibit a skyrmion lattice, such as Cu2OSeO3, GaV4S8 and Co10-xZn10-yMnx+y.
- I am interested in the study of magnetic materials, and in particular oxides which exhibit magnetic long range ordering or geometrical magnetic frustration. My contributions include the growth by the floating zone method, for the first time, of single crystals of frustrated magnets, such as rare earth zirconates and hafnates, R2M2O7 (R = La, Pr, Nd, Sm, Gd; M = Zr, Hf). The magnetic properties of these new crystals of frustrated magnets are still being investigated.
- I am interested in the study of multiferroic compounds and materials that could exhibit magnetoelectric coupling, due to their possible applications in spintronics. My contributions include growth and study of ferromagnets such as R1-xSrxMnO3 (R = Pr, Nd), study of the physical properties and experimental observation, for the first time, of spin waves in single crystals of the candidate magnetoelectric materials, Ga2-xFexO3 ferrimagnets.
My work involves the determination of the crystallographic parameters, the magnetic structure and the spin dynamics of the materials. My expertise in powder and single crystal X-ray and neutron diffraction, muon spectroscopy, as well as inelastic neutron scattering techniques are of great importance for the understanding of the materials studied. I have received training and developed skills in using various software packages (FullProf, Crystals, Jana2006, Shelx, Mantid, Spinwave), that I employ to analyse and interpret the data collected.
Recent publications (2018-2016)
- "Manifolds of magnetic ordered states and excitations in the almost Heisenberg pyrochlore antiferromagnet MgCr2O4".
S. Gao, K. Guratinder, U. Stuhr, J. S. White, M. Mansson, B. Roessli, T. Fennell, V. Tsurkan, A. Loidl, M. Ciomaga Hatnean, G. Balakrishnan, S. Raymond, L. Chapon, V. O. Garlea, A. T. Savici, A. Cervellino, A. Bombardi, D. Chernyshov, Ch. Rüegg, J. T. Haraldsen, and O. Zaharko.
Accepted for publication in Physical Review B (2018).
- "Experimental signatures of emergent quantum electrodynamics in Pr2Hf2O7".
R. Sibille, N. Gauthier, H. Yan, M. Ciomaga Hatnean, J. Ollivier, B. Winn, U. Filges, G. Balakrishnan, M. Knzelmann, N. Shannon, and T. Fennell.
Accepted for publication in Nature Physics (2018).
- "Direct observation of attractive skyrmions and skyrmion clusters in the cubic helimagnet Cu2OSeO3".
J. C. Loudon, A. O. Leonov, A. N. Bogdanov, M. Ciomaga Hatnean, and G. Balakrishnan.
Physical Review B 97, 134403 (2018).
- "Fermi surfaces in Kondo insulators".
H. Liu, M. Hartstein, G. J. Wallace, A. J. Davies, M. Ciomaga Hatnean, M. D. Johannes, N. Shitsevalova, G. Balakrishnan, and Suchitra E Sebastian.
Journal of Physics: Condensed Matter 30, 16LT01 (2018).
- "Disorder and Quantum spin ice".
N. Martin, P. Bonville, E. Lhotel, J. Robert, S. Guitteny, A. Wildes, C. Decorse, M. Ciomaga Hatnean, G. Balakrishnan, I. Mirebeau, and S. Petit.
Physical Review X 7, 041028 (2017).
- "Signatures of the Kondo effect in VSe2".
S. Barua, M. Ciomaga Hatnean, M. R. Lees, and G. Balakrishnan.
Scientific Reports 7, 10964 (2017).
- "New route to a Fermi surface in the absence of a Fermi liquid: a Kondo insulator near the insulator-metal transition".
M. Hartstein, W. H. Toews, Y.-T. Hsu, B. Zeng, X. Chen, M. Ciomaga Hatnean, Q. R. Zhang, S. Nakamura, A. S. Padgett, G. Rodway-Gant, J. Berk, M. K. Kingston, G. H. Zhang, M. K. Chan, S. Yamashita, T. Sakakibara, Y. Takano, J.-H. Park, L. Balicas, N. Harrison, N. Shitsevalova, G. Balakrishnan, G. G. Lonzarich, R. W. Hill, M. Sutherland, and S. E. Sebastian.
Nature Physics 14, 166 (2018).
- "Coulomb spin liquid in anion-disordered pyrochlore Tb2Hf2O7".
R. Sibille, E. Lhotel, M. Ciomaga Hatnean, G. Nilsen, G. Ehlers, A. Cervellino, E. Ressouche, M. Frontzek, O. Zaharko, V. Pomjakushin, H. C. Walker, D. Adroja, H. Luetkens, C. Baines, A. Amato, G. Balakrishnan, T. Fennell, and M. Kenzelmann.
Nature Communications 8, 894 (2017).
- "Probing the interplay between surface and bulk states in the topological Kondo insulator SmB6 through conductance fluctuation spectroscopy".
S. Biswas, M. Ciomaga Hatnean, G. Balakrishnan, and A. Bid.
Physical Review B 95, 205403 (2017).
- "Suppression of magnetic excitations near the surface of the topological Kondo insulator SmB6".
P. K. Biswas, M. Legner, G. Balakrishnan, M. Ciomaga Hatnean, M. R. Lees, D. McK. Paul, E. Pomjakushina, T. Prokscha, A. Suter, T. Neupert, and Z. Salman.
Physical Review B (Rapid Communication) 95, 020410(R) (2017).
- "Single crystal growth, structure and magnetic properties of Pr2Hf2O7 pyrochlore".
M. Ciomaga Hatnean, R. Sibille, M. R. Lees, M. Kenzelmann, V. Ban, V. Pomjakushin, and G. Balakrishnan.
Journal of Physics: Condensed Matter 29, 075902 (2016).
- "Magnetic properties and crystal field in Pr2Zr2O7".
P. Bonville, S. Guitteny, A. Gukasov, I. Mirebeau, S. Petit, C. Decorse, M. Ciomaga Hatnean, and G. Balakrishnan.
Physical Review B 94, 134428 (2016).
- "Antiferroquadrupolar correlations in the quantum spin ice candidate Pr2Zr2O7".
S. Petit, E. Lhotel, S. Guitteny, O. Florea, J. Robert, P. Bonville, I. Mirebeau, J. Ollivier, H. Mutka, E. Ressouche, C. Decorse, M. Ciomaga Hatnean, and G. Balakrishnan.
Physical Review B 94, 165153 (2016).
- "Critical behavior study of Pr1-xSrxMnO3 and Nd1-xSrxMnO3 with x = 1/2".
A. Oleaga, A. Salazar, M. Ciomaga Hatnean, and G. Balakrishnan.
Journal of Alloys and Compounds 682, 825-831 (2016).
- "Candidate quantum spin ice in the pyrochlore Pr2Hf2O7".
R. Sibille, E. Lhotel, M. Ciomaga Hatnean, G. Balakrishnan, B. Fåk, N. Gauthier, T. Fennell, and M. Kenzelmann.
Physical Review B 94, 024436 (2016).
- "Zirconate Pyrochlore Frustrated Magnets: Crystal Growth by the Floating Zone Technique".
M. Ciomaga Hatnean, C. Decorse, M. R. Lees, O. A. Petrenko, and G. Balakrishnan.
Crystals 6, 79 (2016).
- "Observation of magnetic fragmentation in spin ice".
S. Petit, E. Lhotel, B. Canals, M. Ciomaga Hatnean, J. Ollivier, H. Mutka, E. Ressouche, A. R. Wildes, M. R. Lees, and G. Balakrishnan.
Nature Physics 12, 746-750 (2016).
Latest research projects
E. Lhotel, S. Petit, M. Ciomaga Hatnean, J. Ollivier, H. Mutka, E. Ressouche, M. R. Lees, G. Balakrishnan, "Dynamic quantum kagome ice", under review. (link)
Department of Physics
University of Warwick
Coventry CV4 7AL
M dot Ciomaga-Hatnean at warwick dot ac dot uk
A full list of my publications can be accessed here.