Vargas J M, Lima E, Socolovsky L M, Knobel M, Zanchet D, Zysler R D
Centro Atómico Bariloche and Comisión Nacional de Energía Atómica, 8400 San Carlos de Bariloche, Rio Negro, Argentina.
J Nanosci Nanotechnol. 2007 Sep;7(9):3313-7. doi: 10.1166/jnn.2007.688.
Morphological, structural and magnetic properties of 4.8 nm iron oxide nanoparticles have been investigated after annealing under inert atmosphere at different temperatures. The as-prepared iron oxide nanoparticles have been synthesized by chemical route from high temperature reaction of Fe(acac)3 solution in presence of oleic acid and oleylamine surfactant. Annealing the particles at low temperatures (Tann = 573 K) produces an increment of the mean size from 4.8 nm to 6.0 nm, preserving the same morphology. The coercive field of the annealed sample has a small increasing with respect to the as-prepared sample in agreement with the mean particle volume change. Annealing at higher temperature (Tann = 823 K) leads to a bimodal size distribution of the iron oxide nanoparticles with 6.0 nm and 17 nm mean sizes respectively, where the bigger particles dominate the observed magnetic properties.
对4.8纳米氧化铁纳米颗粒在不同温度的惰性气氛中退火后的形态、结构和磁性进行了研究。所制备的氧化铁纳米颗粒通过化学方法由Fe(acac)3溶液在油酸和油胺表面活性剂存在下的高温反应合成。在低温（Tann = 573 K）下对颗粒进行退火会使平均尺寸从4.8纳米增加到6.0纳米，同时保持相同的形态。退火样品的矫顽场相对于制备好的样品有小幅增加，这与平均颗粒体积变化一致。在较高温度（Tann = 823 K）下退火会导致氧化铁纳米颗粒出现双峰尺寸分布，平均尺寸分别为6.0纳米和17纳米，其中较大的颗粒主导了观察到的磁性。
