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Oleg Heczko

Dr. Oleg Heczko

Institute of Physics of the CAS,
Na Slovance 2, Prague  8,18221 Czech Republic
Office phone: +42066052714
E-mail: hez (at) fzu.cz
 

 

 

Research Interests

Experimental research in magnetism, Heusler alloys and particularly of magnetic shape memory and related effects.

 

Scientific career:

I started my research in magnetism already in 1986 at Institute of Physics when I was master student of Faculty of Physics and Mathematics.  After 1992 I spent some time in Finland in Tampere, first on one year course of Materials Science and then in State Research Centre of Finland in Tampere in magnetic characterisation of compacted bulk amorphous and nanocrystalline magnetic materials. After finishing my PhD on this subject back in Prague I went to Salford UK as postdoctoral Royal Society Fellow (1997-98) where my main research field was magneto-optics of ferrite thin films.

After relocation to Helsinki, Finland, thanks to my previous education and research work in the field of magnetism I was asked by Kari Ullakko, discoverer of Magnetic Shape Memory /MSM/ effect to work with him in the field. In this first pioneering stage after discovery we focused on the phenomenology of the effect and its further understanding and development.

The magnetic shape memory effect is new paradigm in the field of the induced deformation caused by magnetic field. It is often compared and also confused with magnetostriction but in contrast with the classical magnetostriction, the strain is caused by structure reorientation by twinning. It differs in magnitude, too. While giant magnetostrictive materials as Terfenol exhibit the “giant” deformation of about 0.2%, the maximum deformation reached up to date in Ni-Mn-Ga based alloys is 12%.

After two year intermezzo in IFW Dresden (2006-2008) focusing to the search and characterisation of MSM in thin films, filaments and other forms, I returned to Prague to the Institute of Physics CAS in 2008 as Purkyně Fellow. Gradually I founded new Magnetic shape memory and magnetocaloric group which become one of the pillars of newly founded department of Functional materials headed by Petr Sittner. From 2014 I am deputy head of the department.

Great boost to our group research capacity is the arrival of Ladislav Straka from Helsinki in 2016, now funded by Czech Science Foundation and future Marie Curie Fellow and planned stay of Robert Niemann from IFW as postdoc in 2017. 

Our group now consists of three senior researchers, two postdocs, four PhD and two master students. Naturally we cooperate and pursue the investigation with many other groups in the institute on particular themes related to magnetic shape memory. 

At present, I am mainly working in the following research areas:

  • development, testing and modelling of magnetic shape memory effects
  • experiments and analysis of physical property changes associated with martensitic transformation in Ni-Mn-based alloy single crystals
  • in-situ investigation of magnetic shape memory alloys by x-ray and neutron diffraction
  • the microscopic origin of the effect
  • development of new alloys exhibiting martensitic transformation as precondition for magnetic shape memory effect

 

Thanks to the successes of the research of MSM in Prague, we manage to get next International Conference of Ferromagnetic Shape Memory Alloys (ICFSMA) to Prague which will be held in June 2019.  I become the chairman of this ongoing ICFSMA conference, which is the most important conference in the field of magnetic shape memory effects.

 

 

Publication Record

  • more than 130 scientific articles in impacted journals
  • 2 book chapters
  • 2 international patents and 1 patent applications

 

Selected Recent Publications

  1. Oleg Heczko, Petr Cejpek, Jan Drahokoupil, Vaclav Holý, Structure and microstructure of Ni-Mn-Ga single crystal exhibiting magnetic shape memory effect analysed by high resolution X-ray diffraction, Acta Materialia 115 (2016) 250-258 http://dx.doi.org/10.1016/j.actamat.2016.05.047
  2. Y. Polyak, V. Drchal, J. Kudrnovský, O. Heczko, J. Honolka, V. Cháb, J. Kopeček, and J. Lančok, Band mapping of the weakly off-stoichiometric Heusler alloy Ni49.7Mn29.1Ga21.2 in the austenitic phase, Phys. Rev. B 91, 165115 (2015). http://dx.doi.org/10.1103/PhysRevB.91.165115
  3. Y. Ge, N. Zarubová, O. Heczko, and S-P. Hannula, Stress-induced transition from modulated 14M to non-modulated martensite in Ni–Mn–Ga alloy, Acta Materialia 90 (2015) 151–160 http://dx.doi.org/10.1016/j.actamat.2015.02.028
  4. Oleg Heczko, Vít Kopecký, Alexei Sozinov, and Ladislav Straka, Magnetic shape memory effect at 1.7K, Appl. Phys. Lett. 103, 072405 (2013); doi: 10.1063/1.4817941 http://dx.doi.org/10.1063/1.4817941
  5. O. Heczko, L. Straka, H. Seiner, Different microstructures of mobile twin boundaries in 10 M modulated Ni–Mn–Ga martensite, Acta Materialia 61 (2013) 622–631. http://dx.doi.org/10.1016/j.actamat.2012.10.007

 

The most quoted:

  1. O. Heczko, A. Sozinov and K. Ullakko, Giant Field-Induced Reversible Strain in Magnetic Shape Memory NiMnGa Alloy, IEEE Trans. Mag., 36, 3266-3268 (2000). http://dx.doi.org/10.1109/20.908764
  2. J. Enkovaara, O. Heczko, A. Ayuela, R.M. Nieminen, Co-existence of ferro- and antiferomagnetic order in Mn-doped Ni2MnGa, Phys. Rev. B, 67, (2003) 212405 http://dx.doi.org/10.1103/PhysRevB.67.212405
  3. O. Heczko, Magnetic shape memory effect and magnetization reversal, J. Magn. Mag. Mat., 290-291, 787 (2005) http://dx.doi.org/10.1016/j.jmmm.2004.11.397
  4. S. Kaufmann, U. K. Roßler, O. Heczko, M. Wuttig, J. Buschbeck, L. Schultz, S. Fähler Adaptive Modulations of Martensites Physical Review Letters  104, 1457029(3), (2010) http://dx.doi.org/10.1103/PhysRevLett.104.145702

 

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