Electron Paramagnetic Resonance of Cr-=SUP=-3+-=/SUP=- Ions in Single Crystals of Yttrium Aluminum Borate YAl-=SUB=-3-=/SUB=-(BO-=SUB=-3-=/SUB=-)-=SUB=-4-=/SUB=--=SUP=-*-=/SUP=-

Single crystal of yttrium aluminum borate YAl_3(BO_3)_4 doped with chromium ions (1 at %) was studied using electron paramagnetic resonance spectroscopy. It is shown that chromium ions introduced into the sample occupy yttrium ion sites in the crystal structure. The parameters of the spin Hamiltonian of Cr^3+ ions in the YАl_3(ВО_3)_4 matrix are determined at different temperatures. The sign of the fine structure parameter D allows the conclusion that the chromium ions in YА1_3(ВО_3)_4 single crystals have an easy-plane anisotropy.