在单相CoO纳米粒子中,大小诱导的交换偏差
Vikash Sharma1, Sudip Pal1, Divya Sharma2
1UGC-DAE Consortium for Scientific Research University campus, Khandwa road, Indore-452001, Madhya Pradesh, India.
Nanotechnology
|April 18, 2024
概括
氧化物 (CoO) 纳米粒子的交换偏差来自于核心外结构. 较小的纳米粒子大小导致了无序的表面旋转,影响了磁相出现和可调节的交换偏差 (EB).
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 纳米技术纳米技术
背景情况:
- 纳米粒子的交换偏差 (EB) 对各种应用至关重要.
- 了解尺寸依赖的磁相转换是控制EB的关键.
- 具有多个磁相的单相材料具有独特的特性.
研究的目的:
- 在单相氧化物 (CoO) 纳米粒子中证明和研究交换偏差 (EB).
- 探索不同的磁相的出现作为晶体大小的函数.
- 阐明表面旋转障碍在观察到的EB现象中的作用.
主要方法:
- 合成具有可控晶体尺寸 (34.6nm和10.8nm) 的CoO纳米颗粒.
- 磁性测量包括零场冷却 (ZFC) 和场冷却 (FC) 磁化.
- 对ac感应性的分析,热延续磁化 (TRM) 和异热延续磁化 (IRM).
主要成果:
- 随着尺寸的减少,CoO纳米颗粒中出现了两个磁相,影响了Nel温度 (TN).
- 在较小的纳米粒子中,在TN以上观察到的磁化不可逆性表明了额外的磁相.
- 有证据表明,有一个核心外结构,一个反铁磁核心和一个无序的铁磁外.
结论:
- 这些CoO纳米粒子的交换偏差源于反铁磁核和无序的表面旋转外之间的交换合.
- 尺寸的缩小导致了非常规的表面旋转动力学,以及缺乏真正的偏磁状态.
- 在CoO纳米颗粒中可调节的EB归因于核心反铁磁性和外旋转障碍之间的相互作用.
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