纳米晶Ni_(1-x)Zn_xFe_2O_4铁氧体粉料的制备及其磁性能研究

Synthesis and Magnetic Properties of Nanocrystalline Ni_(1-x)Zn_xFe_2O_4 Ferrite

采用喷射-共沉淀法制备了纳米晶Ni1-xZnxFe2O4(0≤x≤1．0)铁氧体粉料．通过TG-DSC、XRD、SEM、TEM、BET等测试手段分析了其微观结构和形貌,用振动样品磁强计测量其室温下磁性能．结果表明:喷射-共沉淀法制备的粉料颗粒细小均匀、形状完整．600℃下煅烧1．5h,样品晶粒尺寸为30nm左右,平均颗粒尺寸<100nm．室温下,样品比饱和磁化强度随Zn2+含量增加而变化,当x=0．5时,最大比饱和磁化强度σs为66．8A·m2／kg．当晶粒大小为41nm时,纳米晶．Ni0．5Zn0．5Fe2O4铁氧体矫顽力达到最大值5．06kA／m,随后又随晶粒尺寸增大而减小．这归因于纳米晶软磁材料中强烈的无序磁晶各向异性模式的影响．

Nanocrystalline Nil-xZnxFe2O4 ferrite with 0≤ x ≤1, was successfully prepared by a spraying-coprecipitation method. The microstructure was investigated by using TG-DSC, XRD, SEM, TEM as well as BET. Magnetic properties were measured with a vibrating sample magnetometer （VSM） at room temperature. The results show that uniform and fine nanocrystalline Ni1-xZnxFe204 ferrite powders are obtained by the spraying-coprecipitation method. The grain size is about 30 nm calcined at 600℃ for 1.5h. There are a few agglomerates with average sizes below 100nm. The specific saturation magnetization of nanocrystalline Ni1-xZnxFe2O4 ferrite increases with the concent of Zn^2＋ at room temperature, and maximum as is 66.8A.m^2/kg as the content of Zn^2＋ is around 0.5. When the grain size is 41nm, the coercivity Hc of nanocrystalline Ni0.5Zn0.5Fe2O4 ferrite arrives at 5.06kA/m, and then it decreases with the increase of the grain size. The results may be explained in terms of intense random magnetocrystalline anisotropy model in nanocrystalline materials.