论文标题
COO纳米颗粒的磁相跃迁中的纳米政治性
Nanocriticality in the magnetic phase transition of CoO nanoparticles
论文作者
论文摘要
临界相变的通用理论描述了无限大型系统中二阶相变的临界行为。随着当代对纳米级材料的兴趣的增加，我们通过中子散射研究了COO纳米粒子，并发现了纳米级政权中关键现象理论如何分解。使用COO作为模型系统，我们已经确定了接近抗铁磁相变的尺寸依赖性纳米温度区域，其中纳米粒子的磁相关长度会收敛到恒定值，该磁相关长度明显小于在低温下发现的饱和状态。这与$ t _ {\ rm n} $在批量系统上观察到的$ t _ {\ rm n} $相反。我们在磁相跃迁中对纳米政治性的发现对于理解纳米级相变的重要性至关重要。
The universal theory of critical phase transitions describes the critical behavior at second-order phase transitions in infinitely large systems. With the increased contemporary interest in nanoscale materials, we investigated CoO nanoparticles by means of neutron scattering and found how the theory of critical phenomena breaks down in the nanoscale regime. Using CoO as a model system, we have identified a size-dependent nanocritical temperature region close to the antiferromagnetic phase transition where the magnetic correlation length of the nanoparticles converges to a constant value, which is significantly smaller than that of the saturated state found at low temperatures. This is in clear contrast to the divergence around $T_{\rm N}$ observed for bulk systems. Our findings of nanocriticality in the magnetic phase transition is of great importance for the understanding of phase transitions at the nanoscale.
