Three natural specimens of hematite are characterized using X-ray diffraction, magnetometry, IR/Raman and Mössbauer spectroscopy, with focus on the Morin transition. All are exfoliated by grinding and prolonged sonication in dimethylformamide, followed by centrifuging to extract exfoliated debris from the supernatant. This material is characterized by electron microscopy and atomic force microscopy. There are three main Fe₂O₃ constituents: lamellae that are hundreds of nanometers in diameter and typically 1–10 nm thick, nanoparticles that are about 100 nm in size and ultra-fine nanoparticles smaller than 10 nm. Estimated yield of the lamellae is 10⁻³−10⁻⁴ by volume. All the iron in the debris is antiferromagnetically ordered at room temperature, including 30% that is superparamagnetic and contributes to a quadrupole doublet in the Mössbauer spectrum, but the characteristic weak net moment due to spin canting is absent. Unlike the normal hematite nanoparticles, there is no Morin transition and no net moment in the range of 100 to 300 K. The absence of a net moment is understandable because the lamellae cleave in planes that make small angles with the c-axis.

使用 X 射线衍射、磁力测定、红外/拉曼和穆斯堡尔光谱对三种天然赤铁矿样品进行表征，重点是莫林跃迁。所有的都通过在二甲基甲酰胺中研磨和长时间超声处理而脱落，然后离心以从上清液中提取脱落的碎片。这种材料的特点是电子显微镜和原子力显微镜。存在三种主要的 Fe ₂ O ₃成分：直径数百纳米且厚度通常为 1-10 纳米的薄片、尺寸约为 100 纳米的纳米颗粒和小于 10 纳米的超细纳米颗粒。薄片的估计产量为10 ^-3 -10 ^-4按体积。碎片中的所有铁在室温下都是反铁磁性有序的，其中 30% 是超顺磁性的，并有助于穆斯堡尔光谱中的四极双峰，但由于自旋倾斜导致的特征性弱净矩不存在。与正常的赤铁矿纳米粒子不同，在 100 到 300 K 的范围内没有莫林过渡和净力矩。没有净力矩是可以理解的，因为薄片在与c轴成小角度的平面中劈裂。