Abstract
We report here that the ball-milling process induces the phase transformation from the tetragonal structure to the disordered face-centered-cubic structure in Ni2MnGa ferromagnetic shape-memory alloys. The in situ high-energy x-ray diffraction analyses reveal that an intermediate phase, which is characterized by amorphous structure, controls the transformation kinetics during the postannealing process. Completely different from their coarse-grained counterparts, the ferromagnetic Ni2MnGa nanoparticles undergo various sequences of structural transitions that are tailored by the crystallite size, atomic order, and intrinsic magnetic structure.
Original language | English |
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Article number | 063530 |
Journal | Journal of Applied Physics |
Volume | 101 |
Issue number | 6 |
DOIs | |
State | Published - 2007 |
Funding
J.Q.Y and R.J.M thank Professor P. Canfield for making the magnetic measurement possible. This work is supported by the National Natural Science Foundation of China (Grant No. 50531020) and the National Science Foundation International Materials Institutes (IMI) Program (DMR-0231320) with Dr. C. Huber as the Program Director. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science, under Contract No. DE-AC02-CH11357. Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. W-7405-Eng-82.