脉冲纳米量热法揭示二维CrSBr中层与场依赖的磁有序
Layer- and Field-Dependent Magnetic Order in 2D CrSBr Revealed by Pulsed Nanocalorimetry
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中文总结 AI 辅助
本研究采用脉冲纳米量热法测量CrSBr薄片的磁性质，揭示其层与场依赖的磁有序、层奇偶效应等，确立纳米量热法为低维磁学的有效热力学探针。
中文摘要 AI 辅助
理解二维极限下磁有序的演化仍是范德瓦尔斯磁体领域的核心挑战，其中热力学测量受限于机械剥离薄片的飞克级质量。本研究采用微秒脉冲加热纳米量热法，对CrSBr薄片（直至单层极限）的热容与磁熵进行测量，该测量揭示了与磁有序相关的熵分布，发现层间转变温度降低，且熵衍生的有效磁矩趋近于单层极限。热力学异常捕捉到从类块体层间反铁磁性向层内铁磁关联主导区域的转变；还出现显著的层奇偶效应，奇数层样品呈现与未补偿磁层相关的额外高温贡献。沿易轴施加面内磁场时，反铁磁序被逐步抑制，可提取厚度依赖的临界场，反映层间交换耦合减弱。熵分析进一步揭示，在层间有序转变之上仍存在持续的宽磁涨落区域。综上，这些结果确立纳米量热法为低维磁学的强大热力学探针，可直接获取原子级薄范德瓦尔斯磁体的磁熵、交换相互作用及维度 crossover（转变）信息。
英文摘要
Understanding the evolution of magnetic order in the two-dimensional limit remains a central challenge in van der Waals magnets, where thermodynamic measurements are constrained by the femtogram-scale mass of exfoliated flakes. Here, microsecond pulse-heating nanocalorimetry is used to measure the heat capacity and magnetic entropy of CrSBr flakes down to the monolayer limit. The measurements reveal the entropy landscape associated with magnetic ordering, uncovering a decreasing interlayer transition temperature toward the monolayer limit and an entropy-derived effective moment per layer that increases with thickness toward the expected spin-only scale. Thermodynamic anomalies capture a crossover from bulk-like interlayer antiferromagnetism to a regime dominated by intralayer ferromagnetic correlations. A pronounced layer-parity effect further emerges, with odd-layer samples displaying an additional high-temperature contribution associated with uncompensated magnetic layers. Under in-plane magnetic fields applied along the easy axis, antiferromagnetic order is progressively suppressed, allowing extraction of a thickness-dependent characteristic suppression field reflecting weakened interlayer exchange coupling. Entropy analysis further reveals an extended regime of magnetic fluctuations persisting well above the interlayer ordering transition. Together, these results establish nanocalorimetry as a powerful thermodynamic probe of low-dimensional magnetism, providing direct access to magnetic entropy, exchange interactions, and dimensional crossover in atomically thin van der Waals magnets.
发表机构
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST（加泰罗尼亚纳米科学和纳米技术研究所）
- Universitat Autònoma de Barcelona（巴塞罗那自治大学）
- Université Catholique de Louvain (UCLouvain)（天主教鲁汶大学）
- Institut de Microelectrònica de Barcelona (IMB-CNM-CSIC)（巴塞罗那微电子研究所）
- Columbia University（哥伦比亚大学）
- WEL Research Institute（WEL研究所）
- National Institute for Materials Science（日本国立材料研究所）
机构由 AI 辅助整理，请以论文原文为准。
