Long-distance super-exchange and quantum magnetic relaxation in a hybrid metal-organic framework

• Published in: Chinese physics B 2016-01, Vol.25 (1), p.390-393
• Main Author: 田英 申世鹏 丛君状 闫丽琴 柴一晟 孙阳
• Format: Article
• Language: English
• Subjects: Filing; Hydrogen bonding; Hysteresis loops; Magnetic fields; Magnetic relaxation; Magnetization; Metal-organic frameworks; Metalorganic compounds; Quantum tunnelling; 交换相互作用; 框架; 混合; 磁弛豫; 量子共振; 量子行为; 金属有机; 长距离
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/25/1/017601

The hybrid metal-organic framework [（CH3）2NH2]Fe（HCOO）3 with a perovskite-like structure exhibits a variety of unusual magnetic behaviors at low temperatures. While the long-distance super-exchange through the Fe-（Y-CH-O- Fe exchange path leads to a canted antiferromagnetic ordering at TN - 19 K, a second transition of magnetic blocking develops at TB- 9 K. The stair-shaped magnetization hysteresis loops below TB resemble the behaviors of resonant quantum tunneling of magnetization in single-molecular quantum magnets. Moreover, the magnetic relaxation also exhibits several features of resonant quantum relaxation, such as the exponential law with a single characteristic relaxation time, and the nonmonotonic dependence of relaxation rate on the applied magnetic field with a much faster relaxation around the resonant fields. The origin of quantum tunneling behaviors in the [（CH3）2NH2]Fe（HCOO）3 metal-organic framework is discussed in terms of magnetic phase separation due to the modification of hydrogen bonding on the long-distance super-exchange interaction.