Structure dependence of optical spectra of ferromagnetic Heusler alloy Ni-Mn-Ga

The influence of structural transformation on the optical properties of Heusler alloy Ni-Mn-Ga has been investigated by using Density Functional Theory code CASTEP. The calculated optical refractive and absorption spectra, the off-diagonal components of the dielectric function and the optical conductivity for L21 structure and the tetragonal phase show a noticeable structural dependence which were confirmed by the experiments (Y.V. Kudryavtsev et al., Phys. Rev. B 66 (2002) 115114).