采用水热法在不同条件下制备BiFeO3光催化剂,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和紫外-可见漫反射光谱(UV Vis DRS)等对其进行表征,并以罗丹明B(RhB)溶液为降解物,研究BiFeO3的可见光光催化性能.研究结果表明:制备的BiFeO3光...采用水热法在不同条件下制备BiFeO3光催化剂,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和紫外-可见漫反射光谱(UV Vis DRS)等对其进行表征,并以罗丹明B(RhB)溶液为降解物,研究BiFeO3的可见光光催化性能.研究结果表明:制备的BiFeO3光催化剂具有单一的晶相,粒径为几微米至几十微米,颗粒团聚,吸收的截止波长约为600 nm.BiFeO3颗粒的催化性能表明:中性环境下BiFeO3颗粒对RhB的降解能力很弱,基本对RhB无降解.将体系引入酸性环境,当体系的pH=5时,RhB经过90 min照射,降解率为89.2%;当体系的pH=3时,经过90 min照射,RhB完全降解.说明在模拟太阳光光照下,BiFeO3颗粒对酸性环境下的RhB有良好的光催化降解作用.展开更多
We investigate the dielectric and ferroelectric properties of Sr1-xBixTi1-xFex03 solid solutions （x =0, 0.05, 0.1, 0.15 and 0.2） together with their structures. Through the analysis of Rietveld refinement of powder ...We investigate the dielectric and ferroelectric properties of Sr1-xBixTi1-xFex03 solid solutions （x =0, 0.05, 0.1, 0.15 and 0.2） together with their structures. Through the analysis of Rietveld refinement of powder x-ray diffraction, a cubic structure in space group Pm3m is determined for all the compositions. An obvious dielectric relaxation peak differing from SrTiO3 is observed in the present ceramics. The peak temperature Tm increases with increasing x, and it approaches room temperature at x =0.2. The Vogel Fulcher law and Curie Weiss law fittings further confirm the relaxor ferroelectricity in the present ceramics.展开更多
Polycrystalline antiferromagnetic BiFeO(BFO)thin films were grown on Si/Si O/Ti/Pt(111) substrates by pulsed laser deposition and then ferromagnetic films CoFe(AlSi)(CFAS) by magnetron sputtering. After fabrication, t...Polycrystalline antiferromagnetic BiFeO(BFO)thin films were grown on Si/Si O/Ti/Pt(111) substrates by pulsed laser deposition and then ferromagnetic films CoFe(AlSi)(CFAS) by magnetron sputtering. After fabrication, the films were vacuum-annealed under a 0.1-T magnetic field at different temperatures from 150 to 500 °C.The exchange bias field can be tuned by the annealing temperature for the heterostructures, and the electric domain size can be controlled by the crystal grain size. A large exchange bias of about 5*10T is observed in one of the samples. It can be speculated that the crystal grain sizes are the key element in determining the exchange bias and coercivity of the films annealed at the temperature of higher than Neel temperature(T N) of BFO. Furthermore, it is possible to extend spin theories from single-crystal BFO system to polycrystalline BFO system.展开更多
基金Project of National Natural Science Foundation of China(50872077)Basic Project Supported by the Program of Shaanxi Natural Science(2010JM6013)+2 种基金Project of National Youth Science Foundation(51002092)the Graduate Innovation Found of Shaanxi University of Science and Technology(SUST-A04)the R&D Innovation Team Assistance Fund(TD09-05)
基金Supported by the National Natural Science Foundation of China under Grant Nos 51332006,11274270,and 51272233
文摘We investigate the dielectric and ferroelectric properties of Sr1-xBixTi1-xFex03 solid solutions （x =0, 0.05, 0.1, 0.15 and 0.2） together with their structures. Through the analysis of Rietveld refinement of powder x-ray diffraction, a cubic structure in space group Pm3m is determined for all the compositions. An obvious dielectric relaxation peak differing from SrTiO3 is observed in the present ceramics. The peak temperature Tm increases with increasing x, and it approaches room temperature at x =0.2. The Vogel Fulcher law and Curie Weiss law fittings further confirm the relaxor ferroelectricity in the present ceramics.
基金financially supported by the National Basic Research Program of China (Nos. 2012CB932702 and 2015CB921502)the National Natural Science Foundation of China (Nos. 11174031, 51371024, 51325101, 51271020, and 51471029)
文摘Polycrystalline antiferromagnetic BiFeO(BFO)thin films were grown on Si/Si O/Ti/Pt(111) substrates by pulsed laser deposition and then ferromagnetic films CoFe(AlSi)(CFAS) by magnetron sputtering. After fabrication, the films were vacuum-annealed under a 0.1-T magnetic field at different temperatures from 150 to 500 °C.The exchange bias field can be tuned by the annealing temperature for the heterostructures, and the electric domain size can be controlled by the crystal grain size. A large exchange bias of about 5*10T is observed in one of the samples. It can be speculated that the crystal grain sizes are the key element in determining the exchange bias and coercivity of the films annealed at the temperature of higher than Neel temperature(T N) of BFO. Furthermore, it is possible to extend spin theories from single-crystal BFO system to polycrystalline BFO system.
