Frustrated Magnetism in a Gyroidal Metal–Organic Framework Magnet

Metal–organic frameworks (MOFs) present a diverse chemical platform, leading to innovative breakthroughs in functional materials due to their controllable properties. In recent years, significant progress has been made in the realm of MOF magnets, with a primary emphasis on developing new molecule-based magnets for various applications. Nevertheless, the potential of MOFs as a platform for understanding quantum magnetism is still cultivating. Herein, based on detailed high-magnetic-field experiments on single crystals of Co(II)-oxalate gyroidal MOF, we revealed the competition of multiple quantum magnetic states. Although such phase competition is typically observed in geometrically frustrated magnets, the gyroidal structure does not inherently induce geometric frustration for spins. We propose that in this system, the emergence of bond-dependent anisotropic interactions and tilting of the local trigonal axis lead to the observed competition. This finding unveils the potential of MOF magnets as a novel source of quantum magnetism.