Practical Electron Microscopy and Database

Figure 3035 shows a [110] L1₀ (P4/mmm)-FePt crystal, consisting of a (111) twin in fct (face centered tetragonal) phase structure. The reflections connected by the solid and dashed lines originate from twin and matrix, respectively. The extra weak reflections marked by the white arrowheads in Figure 3036 (a) are from chemical ordering in the L1₀-FePt structure. The twin plane is parallel to (1 -1 -1) or (-1 1 -1)_t, where the subscript “t” represents the twin reflection. The c-axes of the twin and matrix are on the same plane and form a mirror symmetry relative to the (1 -1 -1) or (-1 1 -1)_t twin plane.

[1] Z. R. Dai, Shouheng Sun, and Z. L. Wang, Phase Transformation, Coalescence, and Twinning of Monodisperse FePt Nanocrystals, NANO LETTERS, 1 (8), 443-447, 2001.