Switching the soft shearing mode orientation in Ni-Mn-Ga non-modulated martensite by Co and Cu doping

journal article in Web of Science

English

Resonant ultrasound spectroscopy measurements and density functional theory calculations were used to analyze the effect of Co and Cu doping (3-6 at. %) on elastic constants of non-modulated martensite of the Ni-Mn-Ga ferromagnetic shape memory alloy. Due to the doping, the studied alloys exhibited decreased tetragonal ratios c/a..1.14. Both the experiments and the calculations revealed that the lowering of the c/a ratio resulted in a change of the orientation of the softest shearing modes of the tetragonal lattice. The newly appearing softest shearing modes for the doped materials have approximately {1 a 0 1 c} bcta-1 a 0 1 cnbct orientations and indicate a lattice instability directly related to the particularly low twinning stress for compound {101} a1 01n twins, needed for the magnetically induced reorientation.

magnetic shape memory; elastic constants; acoustic methods; ab initio calculations; resonant ultrasound spectroscopy

BODNÁROVÁ, L.; ZELENÝ, M.; SEDLÁK, P.; STRAKA, L.; HECZKO, O.; SOZINOV, A.; SEINER, H

9. 3. 2020

IOP PUBLISHING LTD

BRISTOL

0964-1726

SMART MATERIALS & STRUCTURES

29

4

United Kingdom of Great Britain and Northern Ireland

045022

-

9

https://iopscience.iop.org/article/10.1088/1361-665X/ab7542