Magnetic two-dimensionality and antiferromagnetism in the DANO crystal.

概要

論文の詳細を見る
An organic free radical crystal, the di-p-anisyl nitric oxide (DANO) crystal, was found to exhibit the characteristics of the two-dimensional Heisenberg spin system in its magnetic susceptibility at low temperatures and in its angular dependence of the ESR line width at room temperature. A distinct minimum of magnetic susceptibility due to a phase transition to antiferromagnetic spin ordering was observed at 1.67 K; this is consistent with the results of the NMR measurements, while another unexplainable anomaly was found near 2.7 K. The magnetic anisotropy field, HA, along the a-axis, perpendicular to the magnetic easy-plane, was determined to be (3±1)×102 Oe at 0 K from the analysis of the antiferromagnetic resonance; it was attributed to the magnetic field originating from the spin magnetic dipoles distributed over the radical molecules. The ratio of the anisotropy field to the exchange field within the magnetic two-dimensional plane, HA⁄HE, and that of the Néel temperature to the Weiss temperature, TN⁄θ, were found to be 5×10−3 and 0.34 respectively. The ratio of the inter-plane exchange interaction to the intra-plane one, J′⁄J, was estimated therefrom to be of the order of 10−3.
公益社団法人日本化学会の論文