Magnetodielectric effect in Ni0.5Zn0.5Fe2O4-BaTiO3 nanocomposites
Magnetodielectric effect in Ni0.5Zn0.5Fe2O4-BaTiO3 nanocomposites
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DOI：
10.1007/s12034-014-0701-2
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发表时间：
2014-05-01
影响因子：
1.8
通讯作者：
Chakravorty, Dipankar
中科院分区：
文献类型：
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作者：
Banerjee, Shilpi;Hajra, Partha;Chakravorty, Dipankar
采用化学方法合成了由Ni0.5Zn0.5Fe2O4 （NZF）和BaTiO3 （BT）纳米颗粒组成的复合材料。颗粒直径在15 ~ 31 nm之间。采用共沉淀法制备NZF。将其浸泡在含有BT的溶胶中，合成的组合物为xNZF-(1 - x) BT，其中x分别= 0.7,0.5和0.3。复合材料表现出由NZF相引起的铁磁磁滞回。通过对矫顽力随温度变化的分析，得到了阻化温度在306-384 K范围内，这与铁氧体纳米颗粒的直径有关。这意味着超顺磁相互作用高于这些温度。由于BT的存在，纳米复合材料还表现出铁电行为，样品的剩余极化很小。在0-0.7特斯拉的磁场范围内，样品表现出磁介电（MD）效应。在最大磁场下测得的MD参数约为2%。这比迄今为止在类似的复合系统中报道的要高一个数量级。这是在两相非均匀介质模型的基础上解释的，两相之间有一个界面，两相具有截然不同的电导率。
Composites comprising of nanoparticles of Ni0.5Zn0.5Fe2O4 (NZF) and BaTiO3 (BT), respectively were synthesized by a chemical method. The particles had diameters in the range of 15-31 nm. NZF was prepared by a coprecipitation technique. This was soaked in a sol containing BT. Compositions synthesized were xNZF-(1 - x) BT, where x = 0.7, 0.5 and 0.3, respectively. The composites showed ferromagnetic hysteresis loops due to NZF phase. The analysis of coercivity variation as a function of temperature gave blocking temperatures in the range of 306-384 K depending on the diameter of the ferrite nanoparticles. This implied that superparamagnetic interactions are above these temperatures. The nanocomposites also exhibited ferroelectric behaviour arising due to the presence of BT. The remanent polarization of the samples was small. This was adduced to the nanosize of BT. The specimens showed magneto-dielectric (MD) effect in the magnetic field range 0-0.7 Tesla. The MD parameter measured at the maximum magnetic field was around 2%. This was one order of magnitude higher than that reported so far in similar composite systems. This was explained on the basis of a two-phase inhomogeneous medium model with an interface between them, the phases possessing drastically different electrical conductivities.