纳米晶复合SrM永磁铁氧体的制备和交换耦合作用

采用sol-gel方法制备M型六角锶铁氧体。利用X光衍射、透射电子显微镜和VSM对纳米晶样品进行了研究。当热处理温度小于 80 0℃ ,样品存在复相。在同样条件下 ,压成薄片的样品存在硬磁与软磁SrFe12 O19/γ Fe2 O3 的纳米复合相的磁性交换耦合作用。温度为 80 0℃的薄片样品 ,比饱和磁化强度σS 为 75 .6emu/g ,内禀矫顽力Hcj 为6 0 15Oe ,最大磁能积 (BH) Max 为 1.87MGOe ,而粉末样品相应的分别为 75 .9emu/ g ,6 40 0Oe和 1.5 2MGOe。当热处理温度大于 85 0℃时 ,只有单一M相

Synthesis and Exchange-coupling Interaction in Nanocomposite SrM Permanent Ferrites

Strontium hexaferrite powders are prepared by the sol-gel method.The samples are analyzed by X ray diffraction(XRD),transmission electron microscope(TEM),and vibrating sample magnetometer(VSM).When thermal treatment temperature is below 800℃,there are two phases of γ Fe 2O 3 and SrFe 12 O 19 .In the same conditions,the samples pressed into a flake exist exchange coupling interaction on the magnetic properties between the two nanostructured phases of γ Fe 2O 3 and SrFe 12 O 19 .At this situation the thermal treatment at 800℃ produces a nanocomposite with a intrinsic coercivity of 6015 Oe,a maximum magnetization at 18 kOe of 75.6 emu/g and a maximum energy product of 1.87 MGOe as compared with the powder sample of 6400 Oe,75.9 emu/g and 1.52MGOe respectively.Only a compound SrFe 12 O 19 is detected over 850℃.