抄録
The nuclear magnetic resonance (NMR) of Fe57 in Ni- and Ni-Zn-ferrites at zero external field was observed by using a pulsed NMR method. The resonance line-widths were too broad to be detected by the steady-state method.
In Ni-ferrite, two resonance lines corresponding to Fe+3 ions at tetrahedral site and at octahedral site were separately observed. At room temperature, the center frequencies of the resonance lines were 67.6 Mc/sec and 72.0 Mc/sec, and their widths were 1.7 Mc/sec and 2.0 Mc/sec, respectively. Temperature dependences were also studied.
The effects of substitution of Zn for Ni on NMR of Fe57 in Ni-ferrite were studied. The NMR signals could be observed up to 30% substitution of Zn at room temperature and up to 50% at liquid air temperature. By substituting Zn for Ni, the resonance line corresponding to octahedral site becomes broader and shifts to the lower frequency side, while that corresponding to tetrahedral site is affected very little.
Mössbauer studies were also carried out to check some of the experimental results and discussions.
