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Combined experimental and theoretical investigation on modulation of multiferroic properties in BiFeO3 ceramics induced by Dy and transition metals co-doping
摘要： Multiferroic Dy and transition metals (Cr, Mn, Ni) co-doped BiFeO3 ceramics were successfully synthesized by a solid-state method, and the influence on the magnetic and ferroelectric properties were investigated. Compared with Bi0.95Dy0.05Fe0.95Mn0.05O3, Bi0.95Dy0.05Fe0.95Cr0.05O3 and Bi0.95Dy0.05Fe0.95Ni0.05O3 ceramics can significantly improve the magnetic properties. The significant enhancement of magnetic properties should be related to the local ferromagnetic coupling from Cr ions (Ni ions) and Fe ions, which have already been proved by first-principles calculations. Meanwhile, both experimental and theoretical studies reveal the Dy substitution can effectively enhance the ferroelectric properties of BiFeO3. Leakage current and conduction mechanism analyses reveal that the improved ferroelectric properties are mainly attributed to the reduced oxygen vacancies.
关键词： Magnetic property,Ferroelectric property,BiFeO3,Substitution
更新于2025-09-23 15:23:52
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Enhanced Photocatalytic Activity by the Combined Influence of Ferroelectric Domain and Au Nanoparticles for BaTiO <sub/>3</sub> Fibers
摘要： Ferroelectric particles have been applied in the photocatalytic field because the spontaneous polarization results in the internal electric field, which can accelerate the separation and migration of photogenerated carriers. In this study, the BaTiO3 (BT) fibers are synthesized by electrospinning. The BT fibers calcined above 800 °C exhibit a strong ferroelectric property, which is verified by a typical butterfly-shaped displacement-voltage loop. It is found that the BT fibers with the single-domain structure exhibit better photocatalytic performance than that with the multi-domain configuration. When the single-domain transforms into multi-domain, the integrated internal electric field correspondingly breaks up, inducing that the internal electric field might cancel each other out and diminish the separation of photogenerated carriers. Also, the Au nanoparticles can improve the photocatalytic activity further on account of the surface plasmon resonance. Therefore, it is suggested that Au nanoparticles decorated on ferroelectric BT nanomaterials are promising photocatalysts.
关键词： photocatalytic performance,Ferroelectric property,domain configuration,internal electric field
更新于2025-09-23 15:23:52
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Highly Sensitive Room-Temperature Sensor Based on Nanostructured K2W7O22 for Application in the Non-Invasive Diagnosis of Diabetes
摘要： Diabetes is one of the most rapidly-growing chronic diseases in the world. Acetone, a volatile organic compound in exhaled breath, shows a positive correlation with blood glucose and has proven to be a biomarker for type-1 diabetes. Measuring the level of acetone in exhaled breath can provide a non-invasive, low risk of infection, low cost, and convenient way to monitor the health condition of diabetics. There has been continuous demand for the improvement of this non-invasive, sensitive sensor system to provide a fast and real-time electronic readout of blood glucose levels. A novel nanostructured K2W7O22 has been recently used to test acetone with concentration from 0 parts-per-million (ppm) to 50 ppm at room temperature. The results revealed that a K2W7O22 sensor shows a sensitive response to acetone, but the detection limit is not ideal due to the limitations of the detection system of the device. In this paper, we report a K2W7O22 sensor with an improved sensitivity and detection limit by using an optimized circuit to minimize the electronic noise and increase the signal to noise ratio for the purpose of weak signal detection while the concentration of acetone is very low.
关键词： non-invasive,biomarker,ferroelectric property,blood glucose,volatile organic compound,acetone,nanostructured K2W7O22,diabetes
更新于2025-09-23 15:21:21
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Nd-Cr co-doped BiFeO3 thin films for photovoltaic devices with enhanced photovoltaic performance
摘要： BiFeO3 films and Nd-Cr co-doped BiFeO3 films were prepared by sol-gel method followed by spinning process on fluorine-doped tin oxide glass substrates. By testing the ultraviolet-visible absorption spectra, it was found that Nd-Cr co-doping will increase the light absorption rate of the film and reduce the optical band gap. The reduced bandgap can facilitate the transport of carriers. After Nd-Cr co-doping, the leakage current of the film is effectively reduced, which is near four orders of magnitude lower than the leakage current density of the pristine BiFeO3 film. The reduction of leakage current will enhance the ferroelectric polarization. The enhancement of ferroelectric polarization is more favorable for the separation of photogenerated carriers. Compared with the pristine BiFeO3 film, the short circuit photocurrent density, open circuit photovoltage and power conversion efficiency of Nd-Cr co-doped BiFeO3 film are all clearly improved. The Nd-Cr co-doped BiFeO3 films exhibited largely enhanced photovoltaic property, which favored the practical application of BiFeO3-based films in photovoltaic devices.
关键词： Element doping,Thin films,Ferroelectric property,Photovoltaic property,Bismuth ferrite,Leakage current
更新于2025-09-23 15:19:57
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Mn-doping composition dependence of the structures, electrical and magnetic properties, and domain structure/switching of Aurivillius Bi5Ti3FeO15 films
摘要： Mn-doped Bi5Ti3FeO15 (BTFO) ?lms were prepared by a chemical solution deposition route. The e?ect of a series of di?erent Mn-doping concentrations from 0.05 to 0.4 on structures, electrical and magnetic properties, and domain structure/switching was systematically studied. Mn-doping into BTFO can avail the grain growth. Ferroelectric and dielectric properties are improved through Mn-doping, and the optimized Mn-doping content is 0.25 with remnant polarization of 17.2 μC/cm2 and permittivity of 371.2 at 10 kHz. Moreover, similar evolution of the permittivity and loss tangent with frequency to that of parent BTFO ?lms appears in the BTFMO ?lms when Mn-doping content is below 0.25, while obvious dispersion phenomena is demonstrated with further increasing Mn-doping content. A 180° domain structure and local ferroelectric switching are observed in all these Mn-doped BTFO thin ?lms, and the piezo-displacement can reach 416 p.m. in 0.15 Mn-doped BTFO ?lm. Finally, ferromagnetic properties appear in all these Mn-doped BTFO thin ?lms. The coercive ?eld shows weak temperature independence on Mn-doping contents, while the remnant magnetization is raised by Mn-doping.
关键词： Domain structure and switching,Dielectric response,Magnetic property,Ferroelectric property,Aurivillius compounds,Element doping
更新于2025-09-19 17:15:36