Liu Qiye, Su Wenjie, Gu Yue, Zhang Xi, Xia Xiuquan, Wang Le, Xiao Ke, Zhang Naipeng, Cui Xiaodong, Huang Mingyuan, Wei Chengrong, Zou Xiaolong, Xi Bin, Mei Jia-Wei, Dai Jun-Feng
College of Integrated Circuits and Optoelectronic Chips, Shenzhen Technology University, Shenzhen, 518118, China.
Department of Physics and Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
Nat Commun. 2025 May 7;16(1):4221. doi: 10.1038/s41467-025-59561-0.
Interlayer magnetic interactions play a pivotal role in determining the magnetic arrangement within van der Waals (vdW) magnets, and the remarkable tunability of these interactions through applied pressure further enhances their significance. Here, we investigate NiI flakes, a representative vdW magnet, under hydrostatic pressures up to 11 GPa. We reveal a notable increase in magnetic transition temperatures for both helimagnetic and antiferromagnetic states, and find that a reversible transition between helimagnetic and antiferromagnetic (AFM) phases at approximately 7 GPa challenges established theoretical and experimental expectations. While the increase in transition temperature aligns with pressure-enhanced overall exchange interaction strengths, we identify the significant role of the second-nearest neighbor interlayer interaction , which competes with intra-layer frustration and favors the AFM state as demonstrated in the Monte Carlo simulations. Experimental and simulated results converge on the existence of an intermediate helimagnetic ordered state in NiI before transitioning to the AFM state. These findings underscore the pivotal role of interlayer interactions in shaping the magnetic ground state, providing fresh perspectives for innovative applications in nanoscale magnetic device design.
层间磁相互作用在决定范德华（vdW）磁体内部的磁排列方面起着关键作用，并且通过施加压力对这些相互作用进行显著调节进一步增强了它们的重要性。在此，我们研究了具有代表性的vdW磁体碘化镍薄片，施加的静水压力高达11吉帕。我们揭示了螺旋磁态和反铁磁态的磁转变温度均显著升高，并且发现在约7吉帕时螺旋磁相和反铁磁（AFM）相之间的可逆转变挑战了既定的理论和实验预期。虽然转变温度的升高与压力增强的整体交换相互作用强度一致，但我们确定了次近邻层间相互作用的重要作用，它与层内失配相互竞争，并如蒙特卡罗模拟所示有利于AFM态。实验和模拟结果都表明在碘化镍转变为AFM态之前存在中间螺旋磁有序态。这些发现强调了层间相互作用在塑造磁基态中的关键作用，为纳米级磁器件设计中的创新应用提供了新的视角。
