High-pressure single-crystal synchrotron diffraction study of MnGe and related compounds

Single crystal synchrotron diffraction for pressures up to 50 GPa has revealed an essential difference in structural properties and compressibility of MnGe compared with Mn1−x Co x Ge and Mn1−x Fe x Ge solid solutions. A negative thermal expansion has been observed for MnGe at low-temperatures and high-pressures. The single crystal refinement has shown a discontinuous change of the atomic coordinates and Mn–Ge interatomic distances of MnGe in contrast to Mn0.1Co0.9Ge. These peculiarities of MnGe are likely to be associated with high-spin–low-spin transition. The relation between anisotropy of the coordination of Mn-atom and its magnetic moment is discussed.