Well-faceted and chemically homogeneous single crystals of BaO-doped lanthanum silicate oxyapatite were grown by a BaCl₂ flux method. They were characterized by optical microscopy, scanning electron microscopy, electron probe microanalysis (EPMA), X-ray diffractometry (XRD), and electrochemical impedance spectroscopy. The developed faces were identified for the two types of single crystals with different habit. The face indices were {100}, {101}, {110}, and {210} for the prismatic crystals, and {100}, {101}, {111}, and {001} for the isometric ones. With prismatic crystals, the general formula was derived from the numbers of cations determined by EPMA and structural data refined by XRD to be (La_10−xBa_x)_Σ=10(Si_5.5+0.25x□_0.5−0.25x)_Σ=6O₂₆ (1.78 ≤ x ≤ 1.81), where □ denotes a vacancy in Si site. We determined the oxide-ion conductivity (σ) of the prismatic single crystal of (La_8.22Ba_1.78)(Si_5.94□_0.06)O₂₆ (x = 1.78) along the elongation direction, which is parallel to the c-axis. The σ-value steadily increased from 7.69 × 10⁻³ to 5.30 × 10⁻² S cm⁻¹ with increasing temperature from 823 to 1073 K. When compared at the same temperature, the σ-values were >230 times higher than those of the randomly grain-oriented polycrystal with the same chemical composition, the latter of which ranged from 1.74 × 10⁻⁵ S cm⁻¹ at 823 K to 2.24 × 10⁻⁴ S cm⁻¹ at 1073 K. The remarkable difference in conductivity between the single crystal and randomly grain-oriented polycrystal was found to be principally induced by the marked conduction anisotropy in the crystal structure.

通过BaCl ₂助熔剂方法生长了BaO掺杂的镧硅酸镧氧基磷灰石的晶面良好且化学均匀的单晶。通过光学显微镜，扫描电子显微镜，电子探针显微分析（EPMA），X射线衍射法（XRD）和电化学阻抗谱对它们进行了表征。识别出具有不同习惯的两种类型的单晶的显影面。棱柱形晶体的面指数为{100}，{101}，{110}和{210}，等角晶面的指数为{100}，{101}，{111}和{001}。对于棱柱形晶体，通式由EPMA确定的阳离子数和XRD精制的结构数据为（La _{10 - x} Ba _x）_{Σ= 10}得出（硅_{5.5 + 0.25 X} □ _{0.5 - 0.25 X}）_{Σ= 6} Ö ₂₆（1.78≤  X  ≤1.81），其中□表示在Si中的网站的空缺。我们 沿着平行于c轴的延伸方向确定了（La _8.22 Ba _1.78）（Si _5.94 □ _0.06）O ₂₆（x = 1.78）的棱柱形单晶的氧化物离子电导率（σ）。所述σ -值稳定地从7.69×10上升^{- 3}至5.30×10 ^{- 2} 小号厘米^{− 1}随温度从823升高到1073K。在相同温度下比较时，σ-值比化学成分相同的无规取向多晶晶体的σ-值高230倍，后者的范围为1.74× 10 ^{- 5} 小号厘米^{- 1}在823K至2.24×10 ^{- 4} 小号厘米^{- 1}在1073 K.在单晶和随机晶粒取向的多晶之间的导电性的显着性差异被发现由标记传导各向异性而主要诱导在晶体结构中。