ORIGIN OF SUPERPARAMAGNETISM IN NICKEL-OXIDE
ORIGIN OF SUPERPARAMAGNETISM IN NICKEL-OXIDE
复制标题
DOI：
10.1063/1.349826
复制
发表时间：
1991-12-01
影响因子：
3.2
通讯作者：
TWIGG, MV
中科院分区：
文献类型：
--
作者：
RICHARDSON, JT;YIAGAS, DI;TWIGG, MV
一段时间以来，已知尺寸小于约100 nm的氧化镍颗粒显示出超顺磁性，该超顺磁性随着颗粒尺寸减小而增加。 造成这种行为的粒子磁矩的起源从未得到充分解释。 这项研究表明，颗粒的大小，而不是还原镍的非化学计量或杂质的存在决定了这一时刻。 关键实验是测量在排除金属镍的条件下制备的氧化镍样品的磁化强度与磁场的关系。 发现几乎相同的结果，为原来的样品，这是黑色的，因此非化学计量的，并在400 K的氢中温和还原后，产生化学计量，并改变颜色为绿色。 对于给定的制备方法，磁化率与粒度成反比。 这是一个简单的模型，不完整的边缘上的边界平面的微晶是一致的，并提供了一个可能的基础，用于测量含氧化镍的样品中的粒度的实用方法。
It has been known for some time that particles of nickel oxide of less than about 100 nm in size show superparamagnetism that increases as the particle size decreases. The origin of the particle magnetic moment responsible for this behavior has never been fully explained. This research indicated that the size of the particle rather than the presence of nonstoichiometry or impurities of reduced nickel determines the moment. The critical experiment was the measurement of magnetization versus magnetic field for a sample of nickel oxide prepared under conditions that preclude metallic nickel. Almost identical results were found for the original sample, which was black in color and thus nonstoichiometric, and after mild reduction in hydrogen at 400 K, which produced stoichiometry and changed the color to green. The magnetic susceptibility was inversely proportional to the particle size for a given method of preparation. This is consistent with a simple model of incomplete edges on the bounding planes of the crystallite and provides a possible basis for a practical method for measuring particle size in nickel oxide-containing samples.