On the phase diagram of erbium

We have examined the magnetic phase diagram of single crystal erbium in applied magnetic fields up to 5.5 T along the c and b-axes using electrical resistance versus temperature and magnetoresistance measurements. The phase diagram for the field along the c-axis generally agrees well with the previous neutron scattering studies by Lin et al. (Phys. Rev. B., 45 (1992) 12873) and McMorrow et al. (J. Phys. Condens. Matter, 4 (1992) 8599). We have observed a splitting of the longitudinal Néel transition as a function of applied magnetic field, and a multicritical point at a field of 2.65 T and 71 K leading to previously unobserved magnetic phases. The phase diagram for the field along the b-axis of Erbium has been determined for the first time. Recently, Jehan et al. (Phys. Rev. B, 50 (1994) 3085) have studied the a-axis phase diagram using neutron scattering. We have used their data along the a-axis in identifying the magnetic structure of our phase diagram for Er along the b-axis.