In SrEr2O4 the magnetic Er ions are linked through a network of triangles and hexagons, where geometrical frustration can arise, provided that some exchange interactions are antiferromagnetic. The compound orders magnetically at 0.75 K in zero field, but the order is incomplete: only one of the two Er sites carries a sizeable magnetic moment. A modest field of approximately 0.4 T applied at base temperature along the c direction destroys the long-range component of magnetic order and locks the system in a short-range strongly diffusive scattering mode. We would like to probe the evolution of the magnetic low-energy excitations in SrEr2O4 in an applied field using a high-resolution neutron scattering spectrometer.