... cation, chiem 1/4 sd hdc. NIU 8 cation M^ ^ chilm cac hdc T, cdn 16 cation Fe^^ chiem cac hdc O thi ferit tuong ling cd cau tnic spinen thuan MlFeFe]04. NIU 8 cation M^ ^ chilm cac hdc ... tu tinh cdc mdu NiFe204nung a 700 C vdi thdi gian nung khdc nhau Mau Thdi gian nung (gid) FWHM Kich thude hat tnmg binh (nm) d3 (A) a (A) He, (Oe) Ms, (emu/g) Mr, (emu/g) Bo 0,5 ... dp Ni^ ^ 2,5.10'^Mvd Fe^" 5.10' ^M Tir ket qua thuc nghiem cho thay kich thude hat niken ferit dieu ehe dugc img vdi ndng do dung dich cac chat dau Ni^ "^ 2,5.10' ^M ...