Positron annihilation study of the Fermi surface of Ni2MnGa

The Fermi surface of the ferromagnetic shape-memory alloy Ni2MnGa has been determined experimentally with two-dimensional angular correlation of electron-positron annihilation radiation. Our results are supported by first principles electronic structure calculations. The measured electron occupancy within the Brillouin zone is consistent with the existence of two nesting features present in the Fermi surfaces calculated in previous studies. The nesting vectors of the calculated Fermi surface match the modulation of the pre-martensitic intermediate structure and that of the martensitic structure. (paper)