NUCLEAR-MAGNETIC-RESONANCE STUDIES OF FE-57 IN BARIUM FERRITE

The nuclear magnetic resonance of Fe57 has been studied in single-crystal and polycrystalline samples of barium ferrite (BeFe12O19). The resonance spectrum has been obtained by plotting the amplitude of the Fe57 spin-echo signals as a function of frequency. The zero-field spectrum has been studied at both 4.2 and 77°K. The spectrum at 4.2°K has also been studied with externally applied static fields of up to 8.8 kG, using oriented single-domain powders. Five hyperfind fields are resolved, corresponding to the five magnetically and crystallographically inequivalent lattice sites of BaFe12O19. Studies of the temperature dependence of the hyperfine fields are made up to 180°K, and the hyperfine fields are compared with those obtained from Mössbauer studies. Values of the hyperfine fields associated with the various crystallographic lattice sites are discussed. © 1969 The American Physical Society.