Group of magnetic shape memory materials "MSM"


Our laboratory focuses on basic research of magnetoelastic multiferroics, especially on materials with magnetic shape memory (Magnetic Shape Memory / MSM materials). It is expected that the investigated materials, mostly based on Heusler compounds, can, due to their special behavior, replace the complicated set that fulfills the winged sentence of the “Material is a machine” field. Such material replaces not only the machine but also serves as a sensor itself. Therefore, they belong to the class of “smart” materials. The advantage of magnetically induced changes is their contactlessness and thus the possibility to influence components remotely and through an impermeable barrier, e.g. in the human body without the need for invasive intervention. The scalability of the phenomenon allows use from large massive components to nano-scale components. Already in the near future, these materials can find applications as energy-saving fast actuators, sensors, active vibration dampers, micro-power generators, and as active and passive elements in micro-mechanical systems. One of the successful prototypical applications of MSM material is magnetically controlled micropump. Under the leadership of experienced workers, Šimon Sukup, a student of the Archbishop's Gymnasium, was able to construct it as part of the Open Science initiative of the Academy of Sciences for secondary schools.

Twinned structure of non-modulated martensite in thin film
Twinned structure of non-modulated martensite in thin film

The research topic of the magnetic shape memory phenomenon was introduced to the Institute of Physics by Dr. Oleg Heczko, Head of Laboratory and Department and an internationally recognized MSM scientist who returned after many years from abroad as Purkyně fellow (2008-2013). He founded and further develops the MSM group. Group mission is to build and maintain a strong, international and internationally recognized presence in the field of magnetic shape memory and subsequently to use the group's expertise to research other magnetic functional materials. Many successful researchers from abroad have been a guest in the group, or directly joined the group; Yanling Ge L. Straka and Dr. Dr. Frans Nielsén from Alto University Finland; Paul Lindquist and Andrew Armstrong of Boise State University, USA; D. Mussiienko of Lapeennranta University of Technology, Finland. The team currently has nine active members.

The availability of state-of-the-art equipment at the Institute of Physics provides broad access to the study of magnetic shape memory material. All starts with the production of alloys in furnaces (eg Bühler Mini Arc Melting System MAM-1, furnace for Bridgman method GRANAT-74) and growth of single crystals in optical zonal furnace, continues by cutting and metallographic processing (specialized laboratory), chemical analysis (MicroXRF Orbis PC Elemental Analyzer System), observation methods of electron microscopy (SEM and TEM, eg Tescan Fera with Xe focused ion beam) and X-ray diffraction (e.g. rotation anode generator RIGAKU), and end e.g. with material characterization on high-end magnetometers in the Joint Laboratory of Magnetic Studies "SLMS". Interesting results are regularly published in international scientific journals and international conferences.

Recent achievements of the group include the prestigious Marie-Curie Individual Fellowship Dr. Ladislav Straka (2017-2019) or confidence in the organization of the international conference ICFSMA 2019 (International Conference on Ferromagnetic Shape Memory Alloys), the most important international conference in the field of magnetic shape memory. The Group is currently seeking to receive another Marie-Curie Individual Fellowship grant focusing on micro-magneto-mechanical systems based on MSM materials.

Selected group's results:

Straka, L., Fekete, L., Rameš, M., Belas, E., Heczko, O., Magnetic coercivity control by heat treatment in Heusler Ni-Mn-Ga(-B) single crystals, Acta Materialia 169 (2019) 109-121. ISSN 1359-6454

Musiienko, D., Straka, L., Klimša, L., Saren, A., Sozinov, A., Heczko, O., Ullakko, K., Giant magnetic-field-induced strain in Ni-Mn-Ga micropillars, Scripta Materialia 150 (2018) 173-176. ISSN 1359-6462. DOI: 10.1016/j.scriptamat.2018.03.020 

Zelený, M., Straka, L., Sozinov, A., Heczko, O., Transformation paths from cubic to low-symmetry structures in heusler Ni2MnGa compound, Scientific Reports 8  (2018) 7275. DOI: 10.1038/s41598-018-25598-z

Heczko, O., Seiner, H., Stoklasova, P., Sedlak, P., Sermeus, J., Glorieux, C., Backen, A., Fahler, S., Landa, M., Temperature dependence of elastic properties in austenite and martensite of Ni-Mn-Ga epitaxial films, Acta Materialia 145 (2017) 298-305. DOI: 10.1016/j.actamat.2017.12.011

Perevertov, O., Heczko, O., Schaefer, R., Direct observation of magnetic domains by Kerr microscopy in a Ni-Mn-Ga magnetic shape-memory alloy, Physical Review B. 95(14) (2017) 144431. ISSN 2469-9950

Straka, L., Drahokoupil, J., Veřtát, P., Kopeček, J., Zelený, M., Seiner, H., Heczko, O., Orthorhombic intermediate phase originating from {110} nanotwinning in Ni50Mn28.7Ga21.3 modulated martensite, Acta Materialia 132 (2017) 335-344. ISSN 1359-6454