Isotopic engineering of `zero-matrix' samarium hexaboride: results of high-resolution powder diffraction and X-ray single-crystal diffractometry studies

Single crystals of the isotopic `zero-matrix' samarium hexaboride (<sup>152</sup>Sm<sup>154</sup>Sm<sup>11</sup>B<sub>6</sub>) have been prepared by a modified variant of the high-temperature solution growth method. The crystals were studied by high-resolution powder (HRP) neutron diffraction and X-ray single-crystal diffractometry. The occurrence of vacancies at the boron site and complete occupancy of the metal site was established from structure refinements. The results obtained demonstrate that the use of the `zero-matrix' effect provides considerably increased precision in determining the structural parameters of atoms in hexaborides when studied by neutron diffraction.