Magnetic Properties Of A Spin-2 Antiferromagnet With Metal-Radical Hybrid Spins

We present an S = 2 antiferromagnet composed of a Mn-verdazyl complex [Mn(hfac)(2)] [o-Py-V-(4-F) 2 ]. An analysis of the magnetic behavior reveals that the strong antiferromagnetic intramolecular interaction between spins on Mn2+ and the verdazyl radical forms an S = 2 hybrid spin below approximately 100 K. In the low-temperature regions, the magnetic susceptibility and the specific heat indicate a phase transition to the three-dimensional order of the S = 2 system. Below the transition temperature, the magnetization curve exhibits a metamagnetic phase transition. From the analysis of electron spin resonance modes, we evaluate the on-site biaxial anisotropy responsible for the anisotropic magnetic behavior.