Synthesis and Physical Properties of Single Crystals and Ceramics of New Ferroelectric BaTi2O5
Synthesis and Physical Properties of Single Crystals and Ceramics of New Ferroelectric BaTi2O5
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DOI：
10.1143/jjap.44.7144
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发表时间：
2005-09
影响因子：
1.5
通讯作者：
Y. Akishige
中科院分区：
文献类型：
--
作者：
Y. Akishige
用浮区法生长了BaTi 2 O 5铁电单晶，测量了其在300-800 K温度范围内的介电常数和比热。沿着b轴的介电常数和介电损耗在TC=730 K处显示出大的介电色散，类似于有序-无序型的铁电相变。计算得到的相变焓和相变熵分别为ΔH= 98.6J/mol和ΔS= 0.136J/molK。晶体的光吸收边在365 nm附近。以二乙醇钡和四异丙醇钛为原料，采用溶胶-凝胶法成功制备了单相BaTi 2 O 5粉体，在1375 K烧结的多孔陶瓷在600 K左右的电容-温度曲线上出现了宽的最大值。
Single crystals of ferroelectric BaTi2O5 were grown by a floating zone method, and the dielectric constant and specific heat were measured in a temperature range of 300–800 K. The dielectric constant and dielectric loss along the b-axis show a large dielectric dispersion at TC=730 K, similar to the ferroelectric phase transition of the order-disorder type. Transition enthalpy and transition entropy were estimated to be ΔH=98.6 J/mol and ΔS=0.136 J/molK, respectively. The optical absorption edge of the crystals exists near 365 nm. Single-phase BaTi2O5 powder was successfully synthesized through a sol-gel route, using barium diethoxide and titanium tetraisopropoxide, and the porous ceramics sintered at 1375 K show a broad maximum in the electrical capacitance vs T curve at approximately 600 K.