Metal Organic Frameworks as Tunable Linear Magnets

Abstract

Due to the tunable magnetic exchange interactions between nearest neighbor moment carriers by exchange linker length or metal ions, metal-organic frameworks (MOFs) in general, and MOF-74 in particular, have promising magnetic properties for novel industrial applications such as magnetic switchers, sensors, and multifunction devices in molecular spintronics. Hence, MOF-74-M [M-2(C8H2O6)] (M = Fe, Co, Ni) possessing a 1D channel is prepared and experimentally examined to describe its diverse magnetic properties, depending on the metal cluster used. By exchanging the metal ion (Fe, Co, and Ni) in the metal cluster, the magnetic state of MOF-74 is changed from ferromagnetic or antiferromagnetic to superparamagnetic. This phenomenon can be also confirmed by alternating current (AC)/direct current (DC) magnetic susceptibility and field-dependent magnetization. Therefore, the intrinsic magnetic properties of MOF-74-M such as blocking temperature, Neel temperature, and interaction energy between metals in magnetic susceptibility tests can be elucidated. Moreover, the superparamagnetic behavior in this system is also observed inM-Hcurves and magnetic dynamics as single-chain magnets. It is believed that MOF-74-M can be utilized for applications in which superconducting materials are required (e.g., memory-storage devices).