Magnetic coercivity control by heat treatment in Heusler Ni-Mn-Ga(-B) single crystals

0509151 - FZÚ 2020 RIV GB eng J - Článek v odborném periodiku
Straka, Ladislav - Fekete, Ladislav - Rameš, Michal - Belas, E. - Heczko, Oleg
Magnetic coercivity control by heat treatment in Heusler Ni-Mn-Ga(-B) single crystals.
Acta Materialia. Roč. 169, May (2019), s. 109-121. ISSN 1359-6454. E-ISSN 1873-2453
Grant CEP: GA ČR GA16-00043S; GA MŠMT(CZ) LO1409
GRANT EU: European Commission(XE) 701867 - FUNMAH
Institucionální podpora: RVO:68378271
Klíčová slova: magnetic shape memory alloys * antiphase boundary * magnetic properties * coercivity * Ni-Mn-Ga
Obor OECD: Condensed matter physics (including formerly solid state physics, supercond.)
Impakt faktor: 7.656, rok: 2019
Způsob publikování: Open access

The combination of enlarged magnetic coercivity and magnetic shape memory (MSM) functionality is essential for novel magnetomechanical effects in MSM alloys. We found that increasing the density of thermal antiphase boundaries (APBs) provides a method to increase the magnetic coercivity without deteriorating the MSM functionality. APB density was controlled by different heat treatments in Ni–Mn–Ga (–B) MSM single crystals with five-layered modulated martensite structure. Slow cooling ∼1 K/min of Ni–Mn–Ga through the B2′–L21 transition resulted in a low density ( < 1/micrometer) of APBs observed by magnetic force microscopy and low coercivity <2 mT. Water quenching resulted in fine magnetic and APB patterns and enlarged the coercivity to 24 mT at room temperature, and this further increased with decreasing temperature up to 41 mT at 10 K.
Trvalý link: http://hdl.handle.net/11104/0299923