Chemical pressure effect in Sm and La substituted ferroelectric BiFeO3 thin films: Insights from infrared spectroscopy
Chemical pressure effect in Sm and La substituted ferroelectric BiFeO3 thin films: Insights from infrared spectroscopy
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DOI：
10.1063/1.4980105
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发表时间：
2017-04-14
影响因子：
3.2
通讯作者：
Kuntscher, C. A.
中科院分区：
文献类型：
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作者：
Burkert, F.;Janowski, M.;Kuntscher, C. A.
通过室温红外反射测量，研究了Sm和La掺杂对BiFeO_3铁电薄膜晶格动力学的影响。在x=0到x=0.25范围内，研究了脉冲激光沉积在SrTiO_3衬底上生长的Bi1-x(Sm，La)(X)FeO_3复合扩散膜中近红外声子模的频率随Sm和La含量的变化。用较小的Sm3+离子取代Bi3+离子，在x约为0.09处出现新相，而在x处的铁电BiFeO_3相约为0.19。相反，对于尺寸相似的La3+离子取代Bi3+离子，发生了从原始BiFeO_3相到新相的连续转变。在这两种情况下，我们将新相指定为顺电正交相。根据Sm掺杂BiFeO_3在x=0.14附近的准同型相界进行了讨论，认为这是提高压电性能的原因。由AIP出版公司出版。
We investigate the effects of Sm and La substitution in ferroelectric BiFeO3 thin films on the lattice dynamics by infrared reflection measurements at room temperature. The frequencies of the infraredactive phonon modes are studied as a function of Sm and La content in Bi1-x(Sm,La)(x)FeO3 composition spread films in the range from x = 0 up to x = 0.25, grown on SrTiO3 substrates by pulsed laser deposition. Substitution of the Bi3+ ions with small Sm3+ ions leads to the appearance of a new phase above x approximate to 0.09 coexisting with the ferroelectric BiFeO3 phase up to x approximate to 0.19. In contrast, for the substitution of Bi3+ ions with La3+ ions of similar size a continuous transition from the original BiFeO3 phase to a new phase takes place. In both cases, we assign the new phase to the paraelectric, orthorhombic phase. These findings are discussed in terms of the morphotropic phase boundary in Sm-doped BiFeO3 around x = 0.14 with a phase coexistence, which was suggested as the origin for enhanced piezoelectric properties. Published by AIP Publishing.