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Subjects Quantum Effects in Organic Ferrimagnetic Chains with Interchain Interactions
Representative researcher Graduated school of Science,Osaka Prefecture University
Yuko HOSOKOSHI
We have developed the study of mixed spin systems with S=1/2 and S=1. Our organic polyradical approach efficiently yielded organic triradials, PNNBNO and BIPNNBNO. In the crystals, BIPNNBNO molecules form ferrimagnetic chains. The large torsion angle between the S=1 and S=1/2 radical planes results in the contacts between not only the nearest neighbouring chains but also the next-nearest neighbouring chains. The system is two dimensional and no magnetic phase transition is observed down to 35 mK. The angular dependence of the linewidth of X-band EPR (electron paramagnetic resonance) shows two-dimensional nature of this material. An anomaly was observed at ca.4 K in the temperature dependence of the static magnetic susceptibility and X-band EPR g-factor, which is related to the spin frustration. The magnetization process exhibits an energy gap below 4.5 T and 1/3 magnetization plateau between 6-23 T. Moreover, very narrow magnetization plateau of 2/3 appears at around 26 T. These properties are related to the quantum effects in organic radical spin systems.