Fig. 4
From: Experimental Exchange Interaction Dataset for Magnetic Materials: Spin Waves to MC Simulations

The diagram illustrates the exchange interaction as a function of the bond angle (M1-L-M2) between magnetic atoms (M1, M2) and the ligand (L), and the interatomic distance (M1-M2). Red and blue circles represent ferromagnetic and antiferromagnetic interactions, respectively. The circle radius is proportional to the square root of the interaction strength, i.e., \(\sqrt{| J| }\).