MAGNETIC PHASE-TRANSITIONS AND MAGNETORESISTANCE IN EASY-PLANE ANTIFERROMAGNETS HOGA2 AND DYGA2

The results of the magnetization and magnetoresistance studies perform ed on single crystals of hexagonal HoGa2 and DyGa2 compounds are prese nted. They have an antiferromagnetic alignment of the magnetic moments of R-ions in the basal plane below the Neel temperatures 7.6 and 11 K respectively. The field-induced multi-step magnetic phase transitions in the basal plane are accompanied by the great changes in the electr ical resistivity of both compounds. Using data on the magnetoresistanc e, two held-induced intermediate phases in HoGa2 are found, when the f ield was applied along the a axis, which is of easy magnetization. The magnetic phase diagram of HoGa2 along a axes is determined.