Synthesis, Characterization, and Structure鈥揚roperty Relationships in Two New Polar Oxides: Zn2(MoO4)(SeO3) and Zn2(MoO4)(TeO3)

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• 作者：Sau Doan Nguyen ; Sang-Hwan Kim ; P. Shiv Halasyamani
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：June 6, 2011
• 年：2011
• 卷：50
• 期：11
• 页码：5215-5222
• 全文大小：976K
• 年卷期：v.50,no.11(June 6, 2011)
• ISSN：1520-510X

文摘

Two new noncentrosymmetric (NCS) polar oxide materials, Zn₂(MoO₄)(AO₃) (A = Se⁴⁺ or Te⁴⁺), have been synthesized by hydrothermal and solid-state techniques. Their crystal structures have been determined, and characterization of their functional properties (second-harmonic generation, piezoelectricity, and polarization) has been performed. The isostructural materials exhibit a three-dimensional network consisting of ZnO₄, ZnO₆, MoO₄, and AO₃ polyhedra that share edges and corners. Powder second-harmonic generation (SHG) measurements using 1064 nm radiation indicate the materials exhibit moderate SHG efficiencies of 100 脳 and 80 脳 伪-SiO₂ for Zn₂(MoO₄)(SeO₃) and Zn₂(MoO₄)(TeO₃), respectively. Particle size vs SHG efficiency measurements indicate the materials are type 1 non-phase-matchable. Converse piezoelectric measurements resulted in d₃₃ values of 14 and 30 pm/V for Zn₂(MoO₄)(SeO₃) and Zn₂(MoO₄)(TeO₃), respectively, whereas pyroelectric measurements revealed coefficients of 鈭?.31 and 鈭?.64 渭C/m² K at 55 掳C for Zn₂(MoO₄)(SeO₃) and Zn₂(MoO₄)(TeO₃), respectively. Frequency-dependent polarization measurements confirmed that all of the materials are nonferroelectric; that is, the macroscopic polarization is not reversible, or 鈥渟witchable鈥? Infrared, UV鈥搗is, thermogravimetric, and differential thermal analysis measurements were also performed. First-principles density functional theory (DFT) electronic structure calculations were also done. Crystal data: Zn₂(MoO₄)(SeO₃), monoclinic, space group P2₁ (No. 4), a = 5.1809(4) 脜, b = 8.3238(7) 脜, c = 7.1541(6) 脜, 尾 = 99.413(1)掳, V = 305.2(1) 脜³, Z = 2; Zn₂(MoO₄)(TeO₃), monoclinic, space group P2₁ (No. 4), a = 5.178(4) 脜, b = 8.409(6) 脜, c = 7.241(5) 脜, 尾 = 99.351(8)掳, V = 311.1(4) 脜³, Z = 2.