Lobo-Checa Jorge, Hernández-López Leyre, Otrokov Mikhail M, Piquero-Zulaica Ignacio, Candia Adriana E, Gargiani Pierluigi, Serrate David, Delgado Fernando, Valvidares Manuel, Cerdá Jorge, Arnau Andrés, Bartolomé Fernando
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009, Zaragoza, Spain.
Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009, Zaragoza, Spain.
Nat Commun. 2024 Feb 29;15(1):1858. doi: 10.1038/s41467-024-46115-z.
Ferromagnetism is the collective alignment of atomic spins that retain a net magnetic moment below the Curie temperature, even in the absence of external magnetic fields. Reducing this fundamental property into strictly two-dimensions was proposed in metal-organic coordination networks, but thus far has eluded experimental realization. In this work, we demonstrate that extended, cooperative ferromagnetism is feasible in an atomically thin two-dimensional metal-organic coordination network, despite only ≈ 5% of the monolayer being composed of Fe atoms. The resulting ferromagnetic state exhibits an out-of-plane easy-axis square-like hysteresis loop with large coercive fields over 2 Tesla, significant magnetic anisotropy, and persists up to T ≈ 35 K. These properties are driven by exchange interactions mainly mediated by the molecular linkers. Our findings resolve a two decade search for ferromagnetism in two-dimensional metal-organic coordination networks.
铁磁性是原子自旋的集体排列，即使在没有外部磁场的情况下，在居里温度以下也能保持净磁矩。在金属有机配位网络中曾有人提出将这种基本特性严格地二维化，但迄今为止尚未通过实验实现。在这项工作中，我们证明了在原子级薄的二维金属有机配位网络中，扩展的协同铁磁性是可行的，尽管单层中只有约5%由铁原子组成。由此产生的铁磁态表现出一个面外易轴方形磁滞回线，具有超过2特斯拉的大矫顽场、显著的磁各向异性，并且在高达T≈35K时仍然存在。这些特性是由主要由分子连接体介导的交换相互作用驱动的。我们的发现解决了在二维金属有机配位网络中长达二十年的铁磁性探索。
