α－Fe_2O_3超微粒的^（57）Fe穆斯堡尔谱

￣(57)Fe Mossbauer Spectrum of α-Fe_2O_3 Ultrafine Particles

利用沉淀法制备α－Ｆｅ＿２Ｏ＿３超微粒，用Ｘ射线衍射仪和扫描电镜对样品的结构和粒度进行了分析，并在室温下测量了不同粒度样品的穆斯堡尔谱。结果表明，α－Ｆｅ＿２Ｏ＿３超微粒存在明显的超顺磁现象，在室温至８０Ｋ的温度范围内测量了一个样品（１７ｎｍ）的穆斯堡尔谱，未见莫林（Ｍｏｒｉｎ）转变．随着粒度和测量温度的改变，样品的穆斯堡尔谱的超顺磁成分、同质异能移位、四极分裂、内磁场都发生了变化。对上述穆斯堡尔参数的变化进行了讨论。

?Fe_2O_3 ultrafine particles were prepared using precipitation method.The sampleswere tested with SEM and X-ray diffraction,The Mossbauer spectra of samples with varioussize were measured at room temperature,the result showed that α-Fe_2O_3 ultrafine particleshave obvious superparamagnetism. The Mossbauer spectra of sample B were measured from295 K to 80 K,no Morin transition was observed in this temperature range. The variationsof superparamagnetic coniponent,isomer shift,quadrupole splitting and internal magneticfield of M6ssbauer spectrum were observed with the changes of grain size and measuringtemperature,the origin of the change of Mossbaruer parameters was discussed.