EN
The new class of magnetic materials with low temperature magnetic relaxation was studied. It was evidenced that the crystal DyAlO_{3} with antiferromagnetically ordered high anisotropy rare-earth ions showed an exponential magnetic relaxation. For the first time low temperature magnetic relaxation was investigated by means of magnetostriction and rare-earth optical absorption spectra instead of standard magnetization measurements. The possible mesoscopic nature of tunneling process was suggested.