MAGNETIC-PROPERTIES OF ULTRAFINE IRON PARTICLES
MAGNETIC-PROPERTIES OF ULTRAFINE IRON PARTICLES
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DOI：
10.1103/physrevb.45.9778
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发表时间：
1992-05-01
影响因子：
3.7
通讯作者：
KOSTIKAS, A
中科院分区：
文献类型：
--
作者：
GANGOPADHYAY, S;HADJIPANAYIS, GC;KOSTIKAS, A
研究了Fe微粒的磁性和形貌特征。 采用气相沉积技术在氩气气氛下制备了Fe超细颗粒。 在蒸发过程中，氩气压力从0.5托变化到8托，并且获得具有对数正态分布的中值直径在50-200埃范围内的样品。 用超导量子干涉仪和穆斯堡尔谱研究了磁性随颗粒尺寸和温度（10 K < T < 300 K）的变化。 粒径小于90埃的样品在室温下表现出超顺磁性行为。 颗粒的饱和磁化强度在25至190 emu/g之间变化，较高的值对应于较大的颗粒。 对于这些较大的颗粒，在室温下获得1.05 kOe的矫顽力。 磁性和结构数据表明，核-壳型结构，其中核由金属Fe组成，壳由Fe氧化物组成。
The magnetic and morphological properties of fine Fe particles have been studied. Ultrafine particles of Fe were prepared using a vapor deposition technique under an argon atmosphere. The argon pressure was varied from 0.5 to 8 Torr during evaporation, and samples with a median diameter in the range 50-200 angstrom were obtained having a log-normal distribution. The dependence of magnetic properties on particle size and temperature (10 K < T < 300 K) were studied using superconducting-quantum-interference-device magnetometry and Mossbauer spectroscopy. Samples with particle diameter below 90 angstrom showed a superparamagnetic behavior below room temperature. The saturation magnetization of the particles varied from 25 to 190 emu/g, with the higher values corresponding to larger particles. For these larger particles, a coercivity of 1.05 kOe was obtained at room temperature. The magnetic and structural data suggested a core-shell type of structure, where the core consists of metallic Fe and the shell is composed of Fe oxides.