中文摘要：

采用X射线劳厄定向法对单晶CeB_6的（110）,（111）,（210）和（310）晶面进行了定向.系统研究了不同晶面热发射性能及磁场对电阻率的影响规律.结果表明,当阴极温度为1873 K时（110）,（111）,（210）和（310）晶面最大发射电流密度分别为38.4,11.54,50.4和20.8 A/cm~2,表现出了发射性能的＂各向异性＂.RichardsonDushman公式计算逸出功结果表明,上述晶面中（210）晶面具有最低的逸出功,为2.4 eV.从实际应用来看,该晶面有望替代商业化的钨灯丝成为新一代的场发射阴极材料.磁电阻率测量结果显示,当晶体从[001]方向旋转至[011]方向时电阻率从73μ？·cm变化至69μ？·cm,表明电阻率在磁场中沿不同方向同样具有＂各向异性＂的特点.

英文摘要：

Cerium hexaboride（CeB_6） as a heavy fermion compound displays a number of interesting low-temperature physical properties such as dense Kondo behavior and a complex magnetic phase diagram due to the interaction between itinerant and local electrons. Recently, the electron emission property of CeB_6 has received much attention because it has potential applications in replacing the commercial LaB_6 cathode and serving as new-generation thermal cathodes. In addition,by comparison with other metal cathodes, it also possesses some advantages, such as a low work function, low volatility,high brightness, thermal stability and high mechanical strength. However, so far the thermionic emission properties of CeB_6 single crystal surfaces except for the（100） surfaces have been rarely reported. Whether the different crystal surfaces of CeB_6 contribute to the various interesting emission properties is main research purpose of the present work.In this paper, the（110）,（111）,（210） and（310） crystal surfaces of single crystal CeB_6 are determined by the X-ray Laue diffraction method, and their thermionic emission current densities are measured at different temperatures and applied voltages. As a result, the maximum emission current densities of the（110）,（111）,（210） and（310） crystal surfaces at 1873 K are 38.4, 11.54, 50.4 and 20.8 A/cm~2, respectively. When their cathode temperatures are all 1773 K, their maximum emission current densities are 15.2, 5.43, 28.0 and 11.44 A/cm~2. In addition, when the cathode temperature decreases to 1673 K, their maximum emission current densities are 4.24, 0.9, 6.2 and 2.43 A/cm~2. It means that the thermionic emissions are strongly anisotropic for the different crystal surfaces. In general, the maximum emission current density of（100） crystal surface of LaB_6 single crystal is about 10 A/cm~2 at 1700 K. By comparing the emission current density of CeB_6 single crystal at 1773 K with that of LaB_6 at 1700 K, it is found that the emission properties of（