Santos Renata V, Cabrera-Pasca Gabriel A, Costa Cleidilane S, Bosch-Santos Brianna, Otubo Larissa, Pereira Luciano F D, Correa Bruno S, Effenberger Fernando B, Burimova Anastasia, Freitas Rafael S, Carbonari Artur W
Programa de Pós-Graduação em Ciência e Engenharia de Materiais - PPGCEM, Universidade Federal do Pará, Ananindeua, PA, 67130-660, Brazil.
Faculdade de Ciências Exatas e Tecnologia, Universidade Federal do Pará, Abaetetuba, PA, 68440-000, Brazil.
Sci Rep. 2021 Oct 25;11(1):21028. doi: 10.1038/s41598-021-99810-y.
We herein report a comprehensive investigation on the magnetic, structural, and electric properties of CoO nanoparticles with different sizes by local inspection through hyperfine interactions measured in a wide range of temperatures (10-670 K) by using radioactive [Formula: see text]In([Formula: see text]Cd) tracers with the perturbed angular correlations technique. Small cobalt oxide nanoparticles with the characteristic size of 6.5 nm have been prepared by the wet chemical route that turned out to be essential to incorporate radioactivity tracers during nucleation and growth of the particles. Nanocrystalline samples with 22.1 nm size were obtained by thermal treatments under low pressure of helium at 670 K. The hyperfine data were correlated with X-ray diffraction, ZFC-FC magnetic measurements, and transmission electron microscopy to describe the structure, magnetic properties, size, and shape of samples. An analysis of the temperature evolution of hyperfine parameters revealed that the structural distortion and the magnetic disorder in the core and on the surface layer play an important role in the magnetic behavior of CoO nanoparticles.
我们在此报告了一项全面研究，通过使用放射性[公式：见正文]In([公式：见正文]Cd)示踪剂和扰动角关联技术，在10 - 670 K的宽温度范围内测量超精细相互作用，对不同尺寸的CoO纳米颗粒的磁性、结构和电学性质进行局部检测。通过湿化学路线制备了特征尺寸为6.5 nm的小氧化钴纳米颗粒，结果表明在颗粒的成核和生长过程中引入放射性示踪剂至关重要。通过在670 K的低压氦气中进行热处理获得了尺寸为22.1 nm的纳米晶样品。将超精细数据与X射线衍射、零场冷却 - 场冷却磁性测量以及透射电子显微镜相关联，以描述样品的结构、磁性、尺寸和形状。对超精细参数的温度演变分析表明，核心和表面层的结构畸变和磁无序在CoO纳米颗粒的磁行为中起着重要作用。
