Detail publikace

Origin of magnetocrystalline anisotropy in Ni-Mn-Ga-Co-Cu tetragonal martensite

ZELENÝ, M. STRAKA, L. RAMEŠ, M. SOZINOV, A. HECZKO, O.

Anglický název

Origin of magnetocrystalline anisotropy in Ni-Mn-Ga-Co-Cu tetragonal martensite

Typ

článek v časopise ve Web of Science, Jimp

Jazyk

en

Originální abstrakt

We investigate the origin of magnetocrystalline anisotropy (MCA) in non-modulated martensite of Ni-Mn-Ga-Co-Cu exhibiting magnetic-field-induced strain up to 12%. Experiments as well as theoretical calculations using density functional theory show that Co and Cu doping or deviation from Ni2MnGa stoichiometry decreases the MCA. As follows from the calculations, the decrease of MCA is much stronger for Cu in Ga sublattice in comparison to Cu in Mn sublattice. The decreasing effect of Co on the MCA is only indirect caused by deficiency in Ni, which is the main element governing the MCA. For further insight, we calculated MCA and magnetic moment as a function of lattice tetragonality c/a. The MCA reaches a maximum at the same c/a where Ni magnetic moment is maximum. However, the tetragonality of equilibrium does not coincide with these maxima. Consequently, in contrast to common expectation, decreasing tetragonality from equilibrium can increase the MCA.

Anglický abstrakt

We investigate the origin of magnetocrystalline anisotropy (MCA) in non-modulated martensite of Ni-Mn-Ga-Co-Cu exhibiting magnetic-field-induced strain up to 12%. Experiments as well as theoretical calculations using density functional theory show that Co and Cu doping or deviation from Ni2MnGa stoichiometry decreases the MCA. As follows from the calculations, the decrease of MCA is much stronger for Cu in Ga sublattice in comparison to Cu in Mn sublattice. The decreasing effect of Co on the MCA is only indirect caused by deficiency in Ni, which is the main element governing the MCA. For further insight, we calculated MCA and magnetic moment as a function of lattice tetragonality c/a. The MCA reaches a maximum at the same c/a where Ni magnetic moment is maximum. However, the tetragonality of equilibrium does not coincide with these maxima. Consequently, in contrast to common expectation, decreasing tetragonality from equilibrium can increase the MCA.

Klíčová slova anglicky

Magnetic shape memory; Magnetocrystalline anisotropy; Ab initio calculations; Ni-Mn-Ga; Ni-Mn-Ga-Co-Cu

Vydáno

01.06.2020

Nakladatel

ELSEVIER

Místo

AMSTERDAM

ISSN

1873-4766

Ročník

503

Číslo

-

Strany od–do

166522–-

Počet stran

8

BIBTEX


@article{BUT163496,
  author="Martin {Zelený} and Ladislav {Straka} and Michal {Rameš} and Alexei {Sozinov} and Oleg {Heczko},
  title="Origin of magnetocrystalline anisotropy in Ni-Mn-Ga-Co-Cu tetragonal martensite",
  year="2020",
  volume="503",
  number="-",
  month="June",
  pages="166522---",
  publisher="ELSEVIER",
  address="AMSTERDAM",
  issn="1873-4766"
}