锌掺杂对铁酸铋薄膜结构及多铁性能的影响

Effect of Zinc Doping on the Structure and Multiferroic Properties of Bismuth Ferrite Thin Films

采用溶胶-凝胶法在Pt/Ti/SiO_(2)/Si衬底上成功制备了BiFe_(1-x)Zn_(x)O_(3)(BFZO)(x=0、2%、4%、6%)(摩尔分数)薄膜,并系统研究了Zn掺杂对BiFeO_(3)(BFO)薄膜结构、表面形貌、漏电流密度、铁电及铁磁性能的影响。XRD图谱显示,所有样品均为钙钛矿结构,无其他杂质相引入。扫描电子显微镜(SEM)测试表明,当Zn掺杂量(x)为4%时,BFZO薄膜表现出均匀的细晶粒和更高的密度,有助于改善漏电流密度。漏电流密度曲线表明,在300 kV/cm的电场下,BiFe_(0.96)Zn_(0.04)O_(3)薄膜的漏电流密度(J)最低为1.56×10^(-6)A/cm^(2),比纯BFO薄膜的低3个数量级。同时,BiFe_(0.96)Zn_(0.04)O_(3)薄膜在室温下表现出较大的剩余极化(2Pr=20.91μC/cm^(2)),是BFO(2P_(r)=4.96μC/cm^(2))的4倍多。此外,Zn掺杂也增强了BFO薄膜的铁磁性能,随着Zn掺杂浓度的提高,BFZO薄膜的饱和磁化强度显著增强,使BiFeO_(3)薄膜在信息存储方面存在潜在的应用价值。

BiFe_(1-x) Zn_(x) O_(3)(BFZO)(x=0,2%,4%,6%)thin films were successfully prepared on Pt/Ti/SiO_(2)/Si substrates by sol-gel method.The effect of Zn doping on the structure,surface morphology,leakage current density,ferroelectric and ferromagnetic properties of BiFeO_(3)(BFO)thin films were investigated systematically.XRD patterns show that all samples match well with the perovskite structure without impurity phase.SEM images show that BFZO thin films with x=4%exhibit uniform fine grains and higher density,which is instrumental for the improvement of leakage current density.The leakage current density curve shows that BiFe_(0.96) Zn_(0.04) O_(3) thin films have the lowest leakage current density(J=1.56×10^(-6) A/cm^(2))under the electric field strength of 300 kV/cm,which is three orders of magnitude lower than that of pure BFO thin films.Furthermore,BiFe_(0.96) Zn_(0.04) O_(3) thin film exhibits the largest remnant polarization(2P_(r)=20.91μC/cm^(2))at room temperature,which is more than four times as large as that of pure BFO(2Pr=4.96μC/cm^(2)).Additionally,compared with BFO thin film,Zn doping also enhances the ferromagnetic properties of BFO thin films,and as Zn doping concentration increases,the saturation magnetization of BFZO thin films is significantly enhanced,which provides potential applications in information storage.