B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Nauky Ave., Kharkiv 61103, Ukraine
Kirensky Institute of Physics, 660036 Krasnoyarsk, Russian Federation
Received August 11, 2017
Experimental AFMR studies of PrFe3(BO3)4 single crystal in a wide frequency range (10–143) GHz at the temperature of 4.2 К have been carried out. It is shown that the high-frequency properties of praseodymium ferroborate are well described in the framework of the model for a two-sublattice antiferromagnet with an easy-axis anisotropy. An energy gap of (134.3±0.5) GHz has been determined, and an effective field of magnetic anisotropy of 1.9±0.1 kOe has been estimated. The results of analysis indicate the spin-orientational phase transition has a first-order character in the studied com-pound.