  The investigations of the interconnection between micro- and macroscopic
properties of materials hosting noncollinear antiferromagnetic ground states
are challenging. These forefront studies are crucial for unraveling the
underlying mechanisms at play, which may prove beneficial in designing cutting
edge multifunctional materials for future applications. In this context, Mn5Si3
has regained scientific interest since it displays an unusual and complex
ground state, which is considered to be the origin of the anomalous transport
and thermodynamic properties that it exhibits. Here, we report the magnetic
exchange couplings of the noncollinear antiferromagnetic phase of Mn5Si3 using
inelastic neutron scattering measurements and density functional theory
calculations. We determine the ground-state spin configuration and compute its
magnon dispersion relations which are in good agreement with the ones obtained
experimentally. Furthermore, we investigate the evolution of the spin texture
under the application of an external magnetic field to demonstrate
theoretically the multiple field-induced phase transitions that Mn5Si3
undergoes. Finally, we model the stability of some of the material's magnetic
moments under a magnetic field and we find that very susceptible magnetic
moments in a frustrated arrangement can be tuned by the field.
