Unexpected modulation revealed by electron diffraction in Ni-Mn-Ga-Co-Cu tetragonal martensite exhibiting giant magnetic field-induced strain

0585050 - FZÚ 2025 RIV GB eng J - Journal Article
Vronka, Marek - Straka, Ladislav - Klementová, Mariana - Palatinus, Lukáš - Veřtát, Petr - Sozinov, A. - Heczko, Oleg
Unexpected modulation revealed by electron diffraction in Ni-Mn-Ga-Co-Cu tetragonal martensite exhibiting giant magnetic field-induced strain.
Scripta Materialia. Roč. 242, Mar (2024), č. článku 115901. ISSN 1359-6462. E-ISSN 1872-8456
R&D Projects: GA MŠMT LM2023051; GA ČR(CZ) GA21-06613S
Institutional support: RVO:68378271
Keywords : ferromagnetic shape memory * crystal structure * structure modulation * Focused ion beam (FIB) * Transmission electron microscopy (TEM)
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 6, year: 2022

Although the modulation of martensite structure has been considered as a precondition for a giant magnetic-field-induced-strain, the largest strain to date has been reported in non-modulated tetragonal martensite of Ni-Mn-Ga-Co-Cu. However, here we found, using high-resolution transmission electron microscopy (HRTEM), that nominally non-modulated tetragonal Ni46Mn24Ga22Co4Cu4 single crystal possesses a modulation. Our observations thus lead back to the original hypothesis that easy twin boundary motion leading to giant magnetic-field-induced-strain is facilitated by a structure modulation.
Permanent Link: https://hdl.handle.net/11104/0352826