Root-mean-square displacements of atoms in the B2- and R-phases of TiNi single crystal

Using Mo Kα radiation on a single crystal of a titanium nickelide, intensities of 15 structural and 11 superstructural reflections of the B2-phase are measured. Structure factors are calculated for these reflections and root-mean-square displacements of nickel and titanium atoms are determined. The mean square displacement of Ni is equal to 〈u2〉Ni = (8.7 ± 0.6) × 10−4 nm2 and is 〈u2〉Ti = (3.9 ± 0.3) × 10−4 nm2 for Ti at 363 K. The temperature dependence of the mean square displacements of Ni and Ti upon cooling is determined in the interval 375–283 K.