Ames Laboratory-US Department of Energy, Ames, Iowa 50011, USA and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588, USA.
Phys Rev Lett. 2014 Jan 31;112(4):045502. doi: 10.1103/PhysRevLett.112.045502. Epub 2014 Jan 28.
Solving the crystal structures of novel phases with nanoscale dimensions resulting from rapid quenching is difficult due to disorder and competing polymorphic phases. Advances in computer speed and algorithm sophistication have now made it feasible to predict the crystal structure of an unknown phase without any assumptions on the Bravais lattice type, atom basis, or unit cell dimensions, providing a novel approach to aid experiments in exploring complex materials with nanoscale grains. This approach is demonstrated by solving a long-standing puzzle in the complex crystal structures of the orthorhombic, rhombohedral, and hexagonal polymorphs close to the Zr2Co11 intermetallic compound. From our calculations, we identified the hard magnetic phase and the origin of high coercivity in this compound, thus guiding further development of these materials for use as high performance permanent magnets without rare-earth elements.
由于无序和竞争多态相的存在，快速淬火导致的具有纳米尺寸的新型相的晶体结构的解析较为困难。计算机速度和算法复杂性的进步现在使得在不假设布拉维晶格类型、原子基础或晶胞尺寸的情况下预测未知相的晶体结构成为可能，为探索具有纳米晶粒的复杂材料的实验提供了一种新方法。通过解决近 Zr2Co11 金属间化合物的正交、三角和六角多晶型体复杂晶体结构中的一个长期存在的难题，展示了这种方法。通过我们的计算，我们确定了该化合物的硬磁相和高矫顽力的起源，从而指导了这些材料作为不含稀土元素的高性能永磁体的进一步发展。
