  Magnetic skyrmions are vortex-like spin textures, which can be manipulated by
external stress or pressure via magnetoelastic effects. Here, we present the
observation of isostructural phase transition in a biskyrmion host hexagonal
MnNiGa at a pressure around 4 GPa using pressure-dependent synchrotron x-ray
powder diffraction (XRD) data analysis. Our XRD data reveals anisotropic
compression behavior with pressure with different compression rates of the
a-axis in the basal plane and the c-axis in the prismatic plane. However, the
hexagonal symmetry remains unchanged for pressure up to 14 GPa. Fitting of unit
cell volume with pressure using a second-order Birch-Murnagan equation of state
reveals that the data to fall into two distinct curves for those above and
below 4 GPa. The present study contributes to the understanding of crystal
structure with the application of hydrostatic pressure in the biskyrmion host
MnNiGa, wherein the skyrmion textures can be manipulated by pressure due to
their magnetoelastic character.
