High field magnetization studies in lithium-zinc ferritea)

The magnetization in Li0.5−z/2ZnzFe2.5−z/2O4 with z=0.0, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 has been measured at 30 K and at applied magnetic fields of up to 100 kOe. The magnetization for samples with z?0.2 saturated at less than 10 kOe. The magnetization for samples with z?0.3 did not saturate. Rather, for applied fields in excess of 30 kOe, these samples exhibited field-independent differential susceptibilities ranging from 1.68×10−5 emu/g-Oe for z=0.3 to 20.66×10−5 emu/g-Oe for z=0.7. The high-field susceptibilities are attributed to localized canting of octahedral site Fe3+ spins with fewer than three tetrahedral site Fe3+ nearest neighbors. Susceptibilities predicted by existing localized canting models are in qualitative agreement with the data, but predicted values for large z are too small.