Preparation And Properties Of Ion-doping BiFeO₃-based Materials

As a typical single-phase multi-ferroic material,Bismuth ferrite?BiFeO₃?has a good prospect in application due to its ferroelectricity and weak ferromagnetism,such as storers,sensors and spintronics.Because it can exhibit both ferroelectric and ferromagnetic properties at room temperature,it has attracted extensive attention from scholars at home and abroad.In this paper,Nd,Pr,BiFeO₃ powder,Nd,Ni co-doped BiFeO₃ powder,Nd,Al co-doped BiFeO₃ powder,Pr,Mn co-doped BiFeO₃ powder and BiFeO₃ based composite powder were prepared by hydrothermal method.What's more,the crystal structure,magnetic properties and photocatalysis of the synthesized powders were investigated by XRD,SEM,IR,PPMS and UV spectrophotometer.The main conclusions are as follows:?1?Pure phase BiFeO₃,Bi_1-xNd_xFeO₃?x=0,0.05,0.1?and Bi_0.95Nd_0.05Fe_1-yNi_yO₃?y=0.02,0.03?powders were synthesized by hydrothermal method.When the Nd is directly doped with BFO,the magnetic properties of the BFO powders increase with the increase of Nd doping amount.Meanwhile,the process of sintering helps to improve the magnetic properties by comparing the powders'magnetic before and after sintering.When Nd,Ni is co-doped with BFO,the magnetic properties increase with the increase of Ni doping amount.The catalytic efficiency is improved with the increase of the Ni doping amount.?2?The pure phase BiFeO₃,Bi_0.95Nd_0.05Fe_1-xAl_xO₃?x=0,0.03,0.05,0.075,0.1?powders were synthesized by hydrothermal method,and the magnetic properties decreased with the increase of Al doping amount,which is because of the non-magnetic ion Al³⁺is introduced into the magnetic ion Fe³⁺site,destroying the Fe-O-Fe network structure,and resulting in the spin-cycloid ordering of the AFM-type sublattice.So with the increase of the amount of Al³⁺substituted Fe³⁺,the magnetic ion reduced,and the exchange interaction is weakened,which cause the decrease in magnetic properties.The catalytic effect increases first and then decreases with the increase of Al doping amount.The best catalytic efficiency at x=0.05 and 120 min.?3?The pure phase BiFeO₃,Bi_1-xPr_xFeO₃?x=0.05 0.1?and Bi_0.95Pr_0.05Fe_1-yMn_yO₃?y=0.05,0.1?powders were synthesized by hydrothermal method.The magnetic properties of Pr were doped with Pr in the single-doped BFO,and the magnetic property of powder is consistent with Pr's amount.The sintering helps to improve the magnetic property.At the same time,the magnetic properties increase with the increase of Mn doping amount during the co-doping of Pr and Mn,which is because of distortion of the BO₆ octahedral,and a new Fe-O-Mn network is formed;What's more,the addition of Mn destroys the spiral antiferromagnetic structure of BFO,which make the interaction between Fe-Mn been much stronger,and thus the magnetic properties are improved.The catalytic efficiency is best at x=0.10,120 min.?4?Pure phase BFO/BNFO,BFO/BNFAO,BFO/BPFO and BFO/BPFMO composite powders were prepared by solid phase sintering at 600?and 800?,respectively.The BFO/B_0.95P_0.05F_0.95M_0.05O₃ sample exhibited the best magnetic property in the BFO/BPFMO composite powders.Whether BFO/BNFO or BFO/BNFMO composite powder,the magnetic property of the sintered samples at 800?are higher than that at 600?.