Ferromagnetic Shape Memory Alloys (FSMA) are active materials that develop high recoverable shape changes under the effect of mechanical stress or magnetic field in very short times (a few milliseconds). Due to their remarkable properties in actuation, vibration damping and sensing have permeated into many industries, such as the biomedical, energy or aerospace. The main objective of this research line is the combination of applied and fundamental research to improve the material performances and the comprehension of the involved physical processes
Shape memory alloys (SMA) are active or multifunctional materials which have a high temperature, high symmetry phase (austenite) and a low temperature, low symmetry one (martensite) (fig. A). They can undergo quite large deformations (up to 20%) when subjected to external stresses in the low temperature phase (super elasticity property), and recover the initial shape when heated to the high temperature phase (memory effect). Super elasticity and memory effect derive from the martensitic transformation. It is a first order thermoelastic transformation driven by mechanical stress or temperature. The transformation is self-accommodating, i.e, from a starting single austenite crystal, several twinned martensite crystals, with their axes oriented in different directions are produced to accommodate the deformation of the lattice. These crystals are called variants or twins and their boundary movement and change of orientation gives rise to the super elasticity. Heating back to the austenite, the single crystal phase and shape are recovered (memory effect).
When these alloys are Ferro-Magnetic (FMSMA), a new parameter enters in to the equation: the external magnetic field H. It can, together with stress and temperature, produce the deformation and change in shape, but without contact (in opposition to stress), and at very high speed (in contrast to temperature), providing a substantial advantage over all known materials for rapid actuation and large stroke in many circumstances (fig. B)
In addition, there are large changes in many properties associated with the martensitic transformation which give rise to multifunctional behavior of these materials. Let’s mention: Giant magnetostriction and magneto-resistance, magneto-caloric and elasto-caloric effects, etc.
The large energy per unit mass of these materials makes them specially interesting for micro and nan o actuators. In this way, thin film cantilevers and sculpted nanopillars are under investigation (fig. C).
The group uses State of the Art experimental techniques for the research in these materials. We can mention: single crystal growth, thin film and combinatorial synthesis, powder and single crystal neutron diffraction (fig. D), large magnetic field European facilities, synchrotron radiation diffraction, absorption and Circular Magnetic dichroism, etc.
Selected publications in the last 5 years:
"Anomalous Hall effect in Ni47.3Mn30.6Ga22.1/MgO(001) thin films", MI Blinov, V Chernenko, VN Prudnikov, IR Aseguinolaza, JM Barandiaran, E. Lahderanta, and A. B. Granovsky, Physical Review B 102 (6), 064413 (2020)
"Role of Fe addition in Ni-Mn-Ga-Co-Cu-Fe ferromagnetic shape memory alloys for high-temperature magnetic actuation", A. Perez-Checa, J. M. Porro, J. Feuchtwanger, P. Lazpita, T. Hansen, C. Mondelli, A. Sozinov, J. M. Barandiaran, K. Ullakko, and V.A. Chernenko, Acta Materialia 196, 549-555(2020)
"Combinatorial synthesis of Ni–Mn–Ga-(Fe, Co, Cu) high temperature ferromagnetic shape memory alloys thin films", V Alexandrakis, JM Barandiaran, A Pérez-Checa, P Lázpita, P Decker, et al, Scripta Materialia 178, 104-107 (2020)
"Submicron pillars of ferromagnetic shape memory alloys: Thermomechanical behavior", IR Aseguinolaza, E Modin, A Chuvilin, JM Barandiaran, VA Chernenko, Applied Materials Today 12, 9-14 (2018)
"Study of the critical parameters for magnetic field-induced strain in high temperature Ni-Mn-Ga-Co-Cu-Fe single crystals", A Pérez-Checa, D Musiienko, A Saren, A Soroka, J Feuchtwanger, A Sozinov, JM Barandiaran, K Ullakko, VA Chernenko, Scripta Materialia 158, 16-19 (2019)
"Antiferromagnetic coupling between martensitic twin variants observed by magnetic resonance in Ni-Mn-Sn-Co films"; V. O. Golub, V. A. Lvov, I. Aseguinolaza, O. Salyuk, D. Popadiuk, Y. Kharlan, G. N. Kakazei, J. P. Araujo, J. M. Barandiaran, and V. A. Chernenko, Physical Review B 95, 024422 (2017)
"Polarized Neutron Study of Ni-Mn-Ga Alloys: Site-Specific Spin Density Affected by Martensitic Transformation"; P. Lázpita, J. M. Barandiarán, J. Gutiérrez, C. Mondelli, A. Sozinov, and V. A. Chernenko, Physical Review Letters 119, 155701 (2017)
"Large tensile superelasticity from intermartensitic transformations in Ni49Mn28Ga23 single crystal"; V. A. Chernenko, E. Villa, D. Salazar, and J. M. Barandiaran, Applied Physics Letters 108, 071903 (2016)
"Self-patterning of epitaxial Ni–Mn–Ga/MgO (001) thin films", IR Aseguinolaza, V Golub, OY Salyuk, B Muntifering, WB Knowlton, P Müllner, JM Barandiarán, VA Chernenko, Acta Materialia 111, 194-201 (2016)
"Spectroscopic Evidence of Band Jahn-Teller Distortion upon Martensitic Phase Transition in Heusler-type Ni-Fe(Co)-Ga Ferromagnetic Shape Memory Alloy Film", K. Sumida, K. Shirai, S. Zhu, M. Taniguchi, M. Ye, S. Ueda, Y. Takeda, Y. Saitoh, I. Rodriguez, J. M. Barandiaran, V. A. Chernenko and A. Kimura, Physical Review B 91, 134417 (2015)