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利用射频磁控溅射技术在LaNiO_3/SiO_2/Si基底上制备了Pb(Mg_(1/3)Nb_(2/3))O_3-PbTiO_3/CoFe_2O_4和Pb(Mg_(1/3)Nb_(2/3))O_3-Pb TiO_3/Co Fe_2O_4/Pb(Mg_(1/3)Nb_(2/3))O_3-PbTiO_3两种复合薄膜.我们采取了三种退火条件对复合薄膜进行退火处理,研究两种复合薄膜的晶体结构、电学和磁学性能.通过对两种复合薄膜的结构的分析,发现两步法退火后得到复合薄膜同时存在纯钙钛矿相和尖晶石相两种结构.铁电性能测试表明,两种复合薄膜均具有较好的铁电性能,其中三层复合薄膜的剩余极化强度Pr最大可以达到14.9μC/cm2,这要归因于多层复合薄膜内部的应力-应变效应和界面耦合效应.在电场强度为80 k V/cm的漏电流密度数量级仅10-5A/cm2,其导电机制在高电场区满足Schottky机制.介频性能测试表明:复合薄膜的介频特性较差,双层复合薄膜的介电性能较好,其介电常数εr为1078,其介电损耗tgδ较大,约为0.43.此外,对复合薄膜的磁滞回线测试表明:两种复合薄膜中均存在磁学性能,且双层结构复合薄膜的铁磁性能较大,其饱和磁化强度Ms为119 emu/cm3,剩余磁化强度Mr达到31.6 emu/cm3,矫顽场Hc为1360 Oe.以上测试结果表明,铁电有序和磁有序可以存在于钙钛矿-尖晶石结构当中,通过多层复合和合适退火方式可以增强其铁电和介电性能.
Pb (Mg 1/3 Nb 2/3) O 3 PbTiO 3 / CoFe 2 O 4 and Pb (Mg 1/3 Nb 2 / Al 2 O 3 were prepared on LaNiO 3 / SiO 2 / Si substrate by RF magnetron sputtering. 3)) two composite films of O_3-Pb TiO_3 / Co Fe_2O_4 / Pb (Mg_ (1/3) Nb_ (2/3)) O_3-PbTiO_3.We annealed the composite films using three annealing conditions. The crystal structure, electrical and magnetic properties of composite films were studied.According to the analysis of the structure of the two kinds of composite films, it was found that there are two structures of the composite films with pure perovskite phase and spinel phase after annealing in two-step method. The electrical property tests show that the two composite films have good ferroelectric properties, of which the maximum remanent polarization Pr of the three-layer composite films can reach 14.9μC / cm2, which is attributed to the stress- Strain effect and interfacial coupling effect.The leakage current density is only 10-5 A / cm2 at the field strength of 80 kV / cm, and its conduction mechanism satisfies the Schottky mechanism in the high electric field.Several frequency performance tests show that the dielectric constant Poor performance, double-layer composite film dielectric properties better, the dielectric constant εr is 1078, the dielectric loss tgδ larger, about 0.43 In addition, The hysteresis loop tests on the composite films show that the magnetic properties of the two composite films both exist and the ferromagnetic properties of the two-layer composite films are large. The saturation magnetization Ms is 119 emu / cm3. The remanent magnetization Mr Reaches 31.6 emu / cm3, and the coercive field Hc is 1360 Oe. The above results show that ferroelectric order and magnetic ordering can exist in the perovskite-spinel structure and can be enhanced by multi-layer compounding and proper annealing Its ferroelectric and dielectric properties.