  The applied magnetic field and temperature phase diagram of the archetypal
frustrated magnet, Gd3Ga5O12, has been reinvestigated using single crystal
magnetometry and polarised neutron diffraction. The updated phase diagram is
substantially more complicated than previously reported and can be understood
in terms of competing interactions with loops of spins, trimers and decagons,
in addition to competition and interplay between antiferromagnetic,
incommensurate and ferromagnetic order. Several additional distinct phase
boundaries are presented. The phase diagram centers around a multiphase
convergence to a single point at 0.9 T and ~ 0.35 K, below which, in
temperature, a very narrow magnetically disordered region exists. These data
illustrate the richness and diversity that arises from frustrated exchange on
the 3 dimensional hyperkagome lattice.
