The magnetic phase diagrams of erbium in the magnetic field–temperature plane have been constructed for applied magnetic fields along the a and b axes. For an a-axis applied field our H–T phase diagrams determined from magnetization and magnetoresistance data are in good agreement and consistent with that of Jehan et al. for temperatures below 50 K. A splitting of the basal plane Néel temperature (TN⊥) above 3.75 T introduces two new magnetic phases. Also a transition from a fan to a canted fan phase as suggested by Jehan et al. is observed in an increasing field below TC. Our phase diagram for a b-axis applied field constructed from magnetization data is very similar to the phase diagram of Watson and Ali using magnetoresistance measurements. However, the anomaly at 42 K reported by Watson and Ali is not observed in the present study. No splitting of the TN⊥ transition is observed in either work for a field applied along the b axis.
Frazer, B. H., Gebhardt, J. R. and Ali, N.. "Magnetic Phase Diagrams of Erbium." (Apr 1999).