Enhanced giant dielectric response in Al-substituted La1.75Sr0.25NiO4 ceramics
Enhanced giant dielectric response in Al-substituted La1.75Sr0.25NiO4 ceramics
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Al 取代的 La1.75Sr0.25NiO4 陶瓷中增强的巨介电响应
DOI：
10.1016/j.jallcom.2010.07.163
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发表时间：
2010-09-24
影响因子：
6.2
通讯作者：
Chen, Xiang Ming
中科院分区：
文献类型：
--
作者：
Liu, Xiao Qiang;Wu, Shu Ya;Chen, Xiang Ming
研究了La1.75Sr0.25Ni1-xAlxO 4（x = 0，0.3）陶瓷的结构和介电性能。在La1.75Sr0.25Ni0.7Al0.3O4陶瓷中发现了单一的四方相，而在La1.75Sr0.25Ni0.7Al0.3O4陶瓷中存在少量的第二相。在这些陶瓷中发现了巨介电响应。用铝离子部分取代镍，提高了介电常数，同时抑制了介电损耗。通过比较介电弛豫和电阻率的激活能，我们得出结论：在La1.75Sr0.25NiO4陶瓷中，重叠的低频介电弛豫主要归因于晶界，而正常的低温弛豫主要归因于体积因子，即热激活的小极化子跳跃。对于La_（1.75）Sr_（0.25）Ni_（0.7）Al_（0.3）O_4陶瓷，低温介电弛豫也主要归因于体积因子。La_（1.75）Sr_（0.25）Ni_（0.7）Al_（0.3）O_4陶瓷的晶界层电容效应增强了介电响应。(C)2010 Elsevier B. V.保留所有权利。
The structures and dielectric properties of La1.75Sr0.25Ni1-xAlxO4 (x = 0, 0.3) ceramics were presented. A single tetragonal phase was found in La1.75Sr0.25NiO4 ceramics, while minor secondary phases were presented in La1.75Sr0.25Ni0.7Al0.3O4 ceramics. Giant dielectric response was found in these ceramics. The dielectric constant was enhanced while the dielectric loss was suppressed by partially substituting nickel with aluminum ions. After comparing the activation energies of dielectric relaxation and electrical resistivity, we concluded that the overlapped low frequency dielectric relaxation was attributed to grain boundaries, while the normal low-temperature relaxation was mainly attributed to the bulk factor, that was, thermally activated small polaronic hopping in La1.75Sr0.25NiO4 ceramics. For La1.75Sr0.25Ni0.7Al0.3O4 ceramics, the low-temperature dielectric relaxation was also mainly attributed to the bulk factor. The enhanced dielectric response should be benefited from the strengthened grain boundary layer capacitor effect in La1.75Sr0.25Ni0.7Al0.3O4 ceramics. (C) 2010 Elsevier B.V. All rights reserved.