Mössbauer Study on the Magnetic Properties of a Single Crystalline Bi₃Fe₅O₁₂ Film

Very recently, an artificial new material “bismuth iron garnet” was prepared for the first time with a reactive ion-beam-sputterring method. A magnetic characterization of this single crystalline garnet film was achieved by applying conversion electron Mössbauer spectroscopy (CEMS). To examine the temperature dependence of sublattice magnetization, CEMS measurments were made at 6, 78, 290, and 670 K, i.e. in both the ferrimagnetic and paramagnetic regions. The magnetic and quadrupole hyperfine interactions as compared with YIG indicated continuous effects of lattice expansion owing to the large spherical size of Bi³⁺ ions. The temperature dependence of sublattice magnetization has been explained by the two-sublattice molecular field model with a molecular field constant N_ad slightly modified from that of YIG.