Strain-Induced Ferroelectricity of a SrTiO_3 Thin Film on a MgAl_2O_4 Su bstrate Observed by Terahertz Time-Domain Spectroscopy
Strain-Induced Ferroelectricity of a SrTiO_3 Thin Film on a MgAl_2O_4 Su bstrate Observed by Terahertz Time-Domain Spectroscopy
复制标题
太赫兹时域光谱观测 MgAl_2O_4 基底上 SrTiO_3 薄膜的应变感应铁电性
DOI：
10.1007/s10762-011-9839-9
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发表时间：
2012
影响因子：
2.9
通讯作者：
金城隆平
中科院分区：
文献类型：
--
作者：
M. Yamamoto;K. Kimura;Y. Harada;and T. Kita;堀陽平・柳井武志・中野正基・福永博俊;松浦祐司;金城隆平
在MgAl2O4（100）衬底上沉积SrTiO3薄膜，其晶格常数比SrTiO3大3.5%。利用太赫兹时域光谱仪测量了SrTiO 3薄膜的介电色散随温度的变化，在170 K附近，薄膜的介电强度和软模频率分别出现了正峰值和负峰值。此外，从理论拟合曲线在千兆赫范围内的介电常数的偏差和阻尼因子的值的增加被观察到低于铁电转变温度。这些现象强烈地表明在170 K附近出现了铁电性。
A SrTiO3thin film was deposited on a MgAl2O4(100) substrate with a 3.5 % larger lattice constant than that of the SrTiO3. The temperature dependence of the dielectric dispersion of the SrTiO3thin film was measured by terahertz time-domain spectroscopy, and the dielectric strength and soft-mode frequency showed positive and negative peaks at around 170 K, respectively. In addition, a deviation of the dielectric constant from the theoretical fitting curve in the gigahertz range and an increase in the value of the damping factor were observed below the ferroelectric transition temperature. These phenomena strongly indicate the emergence of ferroelectricity at around 170 K.