Electronic Structure and Structural Transformation of Co_{1-x}Ni_{1+x}Al (x=0, \pm 1/2)
نویسندگان
چکیده
To expand our knowledge of the martensitic transformation from a B2 to an L10 structure for ferromagnetic shape memory Co-Ni-Al alloys, we have performed first-principles band calculations for the supercell structures corresponding to Co1 xNi1þxAl (x 1⁄4 0, 1=2) in a nonmagnetic state. From the investigation of total energy vs c=a, we have found that the total-energy gain for x 1⁄4 0 due to the distortion is 3 4 times as large as those for x 1⁄4 1=2. This result indicates that the stabilization of an L10 structure becomes weak in a rich Co or Ni region compared with the composition of Co:Ni:Al = 1:1:1. We have discussed the result in terms of band energy and such components as CoAl, NiAl, CoNi and etc., which compose Co1 xNi1þxAl.
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