强耦合磁失措自旋冰系统Dy2Ti2O7单晶生长和基本磁性质测量

利用红外光源浮区法生长出大尺寸、高质量的磁失措自旋冰化合物Dy₂Ti₂O₇单晶体.X射线衍射实验证实晶体具有面心立方结构，空间群为Fd3m，晶胞参数a＝1.0112(2) nm，［111］和［400］方向X射线衍射摇摆曲线半高宽分别仅为0.07°和0.05°.直流磁化率与温度关系测量给出晶体的Van Vleck顺磁因子为2.46×10^-5 m³/mol，有效磁矩μ_eff＝10.24(4)μ_B，Cure-Weiss温度Θ_CW＝1.1 K，揭示Dy₂Ti₂O₇具有弱的铁磁性.对磁性起源的综合分析表明，该自旋冰晶体磁性质主要来源于磁偶极相互作用，且相关最近邻长程偶极相互作用能量标度D_nn＝3.00 K. 关键词： 2Ti₂O₇')" href="#">Dy₂Ti₂O₇ 浮区法晶体生长 关联电子系统 自旋冰

Single crystal growth and magnetic properties of strong geometric frustrated magnetic pyrochlore Dy2Ti2O7

Large, high quality single crystals of Dy₂Ti₂O₇ have been successfully grown by the floating zone technique in an infrared image furnace. The obtained single crystal has been characterized by X-ray diffraction at room temperature and is shown to have the face centred cubic structure, Fd3m, with a room temperature lattice parameter a＝1.0112(2) nm. The full-width at half-maximum of rocking curves of ［111］ and ［400］ Bragg peaks are 0.07° and 0.05°, respectively. Magnetic susceptibility measurements give a Van Vleck paramagnetic parameter of 2.46×10^-5m³/mol, the effective moment μ_eff＝10.24(4)μ_B and Cure-Weiss temperature Θ_CW＝1.1 K, indicating weak ferromagnetism for the Dy₂Ti₂O₇ single crystal. The comparative studies of the experiment and theoretical analysis reveal that the long-ranged dipole-dipole interactions dominate the magnetic behaviors of this kind of spin ice system, and the dipolar energy scale D_nn=3.00 K.