Magnetic Properties of NiZnFe_2O_4 Spinels Prepared from Layered NiZn-Fe(II)-Fe(III) Hydrotalcite Precursors

The single phase spinel NiZnFe2O4 ferrite was prepared by calcining layered NiZn-iron(Ⅱ)-iron(Ⅲ) hydrotalcite precursors.The hydrotalcite with different Ni2+∶Zn2+∶Fe2+∶Fe3+ molar ratios of 1∶2∶5∶2,3∶3∶10∶4,2∶1∶5∶2,5∶1∶10∶4 were prepared.The effect of reaction condition on the crystal structure was also investigated.The layered double hydroxide(LDH) and resulting hydrotalcite calcined products were characterized by XRD,IR,TG-DTA and VSM.The results showed when the molar ratio of Ni2+∶Zn2+∶Fe2+∶Fe3+ in the mixture was 3∶3∶10∶4,the material obtained by calcining the resulting hydrotalcite was a single phase spinel and the sample exhibited excellent magnetic properties with intensity of saturation 78.89 A·m2·kg-1.