Anisotropic Magnetic Properties and Anomalous Thermal Conductivity in the bc Plane of the Quasi-Two-Dimensional Spin System Cu_3B_2O_6 : Relation between the Thermal Conductivity and the Spin State in Magnetic Fields

概要

論文の詳細を見る
We have measured the magnetic susceptibility in a magnetic field of 1T (rotating the field direction) in the he plane, the magnetization curve in magnetic fields up to 30T and the thermal conductivity in magnetic fields up to 14T for the quasi-two-dimensional spin system Cu_3B_2O_6 Two-fold symmetry of the susceptibility in the he plane has been found to develop at low temperatures below the Neel temperature T_N = 10K. This is understood on the basis of the low symmetry of the Cu-O-Cu network. The susceptibility does not appear to vanish as T → OK even in the direction where the magnetization exhibits the minimum, indicating that the spin arrangement in the bc plane at T < T_N is noncollinear. The magnetization curve exhibits a bend and/or a jump associated with either spin-flop or metamagnetic transition at T < T_N, depending on the field direction. The thermal conductivity along the direction where the magnetization exhibits the minimum in the he plane has been found to exhibit marked enhancement and a peak at T < T_N , which is understood to be caused by the increase of the thermal conductivity due to magnons. The peak is suppressed with increasing magnetic-field below 12T and tends to recover in high field above 12T. It has been found that the thermal conductivity strongly correlates with the spin slate in Cu_3B_2O_6
社団法人日本物理学会の論文
2003-03-15