In hematite crystals doped with gallium and dysprosium ions a spin-reo
rientation phase transition induced in the basal plane by the introduc
tion of dysprosium ions was observed in the temperature range T = 15-2
0 K. The effect is associated with the competition between the anisotr
opy fields arising from the iron and rare-earth subsystems. (C) 1996 A
merican Institute of Physics.