Effect of Zn2+ on structure, magnetic properties and thermomagnetic effect of MnZn ferrites

MnZn ferrite nanoparticles were prepared by using sol-gel auto-combustion method. The effect of Zn2+ on structure, magnetic properties and thermomagnetic effect were investigated with transmission electron microscope (TEM), X-ray diffractometer (XRD) and vibration sample magnetism analysis system (VSM), etc. The results show that Zn2+ has great influence on structure and property of MnZn ferrite. Among the samples prepared, Mn0.8Zn0.2Fe2O4 possessed the maximal saturation magnetization Ms and thermomagnetic effect. 10 mg these samples led the 1 mL deionized water increase 32°C in 20min under a 60kHz alternating magnetic field, showing the sufficient heating ability. Furthermore, the thermomagnetic effect of MnZn ferrite was adjustable by adjusting Zn2+ content. When the Zn2+ content increases, the coercive force Hc and remnant magnetization Br reduce, but the saturation magnetization Ms increases first and reduces subsequently, the maximal Ms to be obtained while the Zn2+ content is 0.2, the utmost value is up to 44.6 (A · m2)/kg.