Background

I joined the Superconductivity and Magnetism Group at Warwick as a Postdoctoral Research Fellow in January 2017 as a part of The Skyrmion Project, where I worked with Professor Geetha Balakrishnan.
I completed a Ph.D. in Chemistry at Durham University in 2017 under the supervision of Professor Andrew Beeby. The family of materials I discovered during my Ph.D. work and as post graduate researcher at Jožef Stefan Institute are strongly correlated systems exhibiting a variety of magnetic properties, spanning antiferromagnetism, ferromagnetism, canted-antiferromagnetismm, low-dimensional magnetism and superconductivity. I have performed the characterisation of the obtained novel organic magnets by laboratory- and synchrotron-based (ESRF) x-ray diffraction (also following structural phase transitions and negative thermal expansions), SQUID magnetometry at ambient and hydrostatic pressure, Raman and muon spectroscopy (ISIS). Some of the results are gathered in my thesis and in the publications listed below.

Research Interests

At Warwick my research involved the synthesis and characterisation of Skyrmion hosting materials. By utilising chemical vapour transport method I have successfully grown single crystals of Cu₂OSeO₃, Zn-substituted Cu₂OSeO₃ and the family of GaV₄S_(8-y)Se_(y) (y ranges between 0.5 and 7.5), hosting both Bloch and Néel types of Skrmions. The Bridgman and modified Bridgman techniques were used for growth the single crystal grains of (Mn_0.5Ni_0.5)₆₅Ga₃₅, Mn_1.4Pt_0.9Pd_0.1Sn and Co_(10-x)Zn_(10-y)Mn_(x+y) intermetallic compounds hosting ‘biskyrmions’, antiskyrmions and Bloch type Skyrmions respectively. The single crystals of Gd₂PdSi₃, where the frustration is the driving force for skyrmion lattice formation instead of DMI, were grown by the optical floating zone method. The detailed structural characterisation of these materials was achieved by laboratory and synchrotron based single crystal and powder diffraction (Diamond), including anomalous X-ray scattering, along with powder (ILL) and single crystal (ISIS) neutron diffraction. The magnetic properties were investigated by DC- and AC-SQUID magnetometry. I have used Olex2, Jana2006, TOPAS-Academic V6 and Expo2014 to analyse the obtained data.

Publications

• J. C. Loudon, A. C. Twitchett-Harrison, D. Cortés-Ortuño, M. T. Birch, L. A. Turnbull, A. Štefančič, F. Y. Ogrin, E. O. Burgos-Parra, N. Bukin, A. Laurenson, H. Popescu, M. Beg, O. Hovorka, H. Fangohr, P. A. Midgley, G. Balakrishnan, and P. D. Hatton, Do Images of Biskyrmions Show Type-II Bubbles?, Advanced Materials 31, 1806598 (2019).

• M. T. Birch, R. Takagi, S. Seki, M. N. Wilson, F. Kagawa, A. Štefančič, G. Balakrishnan, R. Fan, P. Steadman, C. J. Ottley, M. Crisanti, R. Cubitt, T. Lancaster, Y. Tokura, and P. D. Hatton, Increased lifetime of metastable skyrmions by controlled doping, Physical Review B 100, 014425 (2019).

• K. J. A. Franke, B. M. Huddart, T. J. Hicken, F. Xiao, S. J. Blundell, F. L. Pratt, M. Crisanti, J. Barker, S. J. Clark, A. Štefančič, M. Ciomaga Hatnean, G. Balakrishnan, and T. Lancaster, "Magnetic phases of skyrmion-hosting GaV4S8−ySey (y=0,2,4,8) probed with muon spectroscopy", Physical Review B 98, 054428 (2018).

• A. Štefančič, G. Klupp, T. Knaflič, D. S. Yufit, G. Tavčar, A. Potočnik, A. Beeby and D. Arčon, “Triphenylide-Based Molecular Solid—A New Candidate for a Quantum Spin-Liquid Compound”, The Journal of Physical Chemistry C 121 (27), 14864-14871 (2017).

• Y. Takabayashi, M. Menelaou, H. Tamura, N. Takemori, T. Koretsune, A. Štefančič, G. Klupp, A. J. C. Buurma, Y. Nomura, R. Arita, D. Arčon, M. J. Rosseinsky and K. Prassides, “π-electron S = ½ quantum spin-liquid state in an ionic polyaromatic hydrocarbon”, Nature Chemistry 9, 635-643 (2017).

• B. Alič, A. Štefančič and G. Tavčar, “Small molecule activation: SbF3 auto-ionization supported by transfer and mesoionic NHC rearrangement”, Dalton Transactions 46, 3338 (2017).

• A. Štefančič, D. Primc, G. Tavčar and T. Skapin, “Direct solvothermal preparation of nanostructured fluoride aerogels based on AlF₃”, Dalton Transactions 44, 20609 (2015).

Submitted publications

• A. Štefančič, S.H. Moody, T.J. Hicken, T.M. Birch, G. Balakrishnan, S.A. Barnett, M. Crisanti, J.S.O. Evans, S.J.R. Holt, K.J.A. Franke, P.D. Hatton, B.M. Huddart, M.R. Lees, F.L. Pratt, C.C. Tang, M.N. Wilson, F. Xiao, and T. Lancaster, “Origin of skyrmion lattice phase splitting in Zn-substituted Cu2OSeO3”

Write to

If you have any questions about the research work carried out by Dr Ales Stefancic while at Warwick please email:

G dot Balakrishnan at warwick dot ac dot uk

Contact Details

Ales Stefancic

Paul Scherrer Institute
Forschungsstrasse 111
5232 Villigen PSI
Switzerland

Telephone

+41 56 310 27 45

ales dot stefancic at psi dot ch