Spectral and magnetooptical study on spin reorientation phenomenon in ErFeO3

A visual study on the domain structure of ErFeO3 in the spin - reorientation (SR) region by the Faraday effect method is made. To elucidate the role of the Er3+-Fe3+ exchange interaction, the absorption spectrum of ion Er3+ is studied in the sup(4)Isub(15/2)→sup(4)Fsub(3/2) transition region. It is shown that the domain structure and optical absorption spectrum of ErFeO3 reveal certain specific features in the range of temperatures T1<=T<=T2 associated with SR. At temperatures T2=(100+-1) K and T1=(88+-1) K the specific features are typical for a second-order phase transformation, that is consistent with results obtained by other methods. It is shown that the optical spectroscopy can provide information on the phenomenon of low-temperature SR in the case of magnetic dielectrics containing Kramers rare-earth ions