The terahertz (THz) spectral range offers a platform for experimentally collecting electromagnetic pulses to analyze the intrinsic resonances of matter and has become an important field for applying intrinsic responses to future information devices. However, a lack of numerical methods for signal denoising exists in the knowledge of the THz spectral range. In this paper, numerical methods that employ the Bézier curve and its generalization ( B -spline) to denoise thermally tunable and thickness-dependent terahertz signals are proposed. Different thicknesses of ErFeO 3 are chosen and prepared. Both Bézier curves and B -splines have the ability to denoise the signals and the effect of the Bézier curves on the noise is close to but slightly less than that of the B -splines. Additionally, the B -splines show a better noise reduction effect and have better signal strength stability and robustness than do the Bézier curves. Thus, B -splines are applied to process the raw data, and quantitative insight into the trend of the resonant frequencies, peak heights, and transmittances of antiferromagnetic resonance and ferromagnetic resonance with temperature is obtained.
Fu Qiyuan,Long Jingyu,Gao Shuang,Tu Wenjun,Teng Runduo,Lan Tianyu,Feng Changhao
Acetone is a common industrial chemical that can irritate the respiratory tract, damage the central nervous system, and pose health risks; it is also highly flammable and poses explosion hazards. Therefore, real-time detection of acetone is of paramount importance. In this study, acetone gas sensors were successfully fabricated with ErFeO 3 nanofibers doped with yttrium at different concentrations (0, 2, 4, and 6 at%), which were synthesized by a facile electrospinning method, and their gas-sensing properties were systematically investigated. Experimental results demonstrated that Y (yttrium) doping significantly enhances the gas-sensing performance of ErFeO 3 nanofibers. Specifically, EFO-4Y (Y/Er ratio = 4 at%) exhibited a response of 13.66 to 10 ppm acetone at 150 °C, representing a 2.29-fold increase compared to pure EFO. These sensors also demonstrated excellent selectivity, repeatability, and long-term stability. Compared with other reported acetone sensors, this sensor offers advantages including a simple synthesis method, a lower operating temperature, and a reduced detection limit (LOD). Consequently, Y-doped ErFeO 3 nanofibers can serve as a promising material for detecting low-concentration acetone.
To detect volatile organic compounds, fabricating gas sensors with high sensitivity, excellent selectivity, low detection limits, and good long-term stability is critical. Herein, Er1/3Yb1/3La1/3FeO3medium-entropy material was synthesized via the sol–gel method and characterized in terms of its morphological, structural, and chemical properties. The medium-entropy design induces significant lattice distortion and increased oxygen vacancies, leading to higher adsorbed oxygen content and hole concentration on the material surface, which enhances the activity of gas-sensing reactions. The Er1/3Yb1/3La1/3FeO3sensor exhibits a response of 13.2 toward 10 ppm of butanone gas at the optimum operating temperature of 192 °C, which is nearly three times the response of the ErFeO3sensor (4.5), along with excellent selectivity to butanone gas, a low detection limit (0.5 ppm), and long-term stability. Moreover, the applied magnetic fields improve the ordering of magnetic moments in both Er1/3Yb1/3La1/3FeO3and O2molecules, which facilitates gas adsorption and electron transfer, and further boosts the gas-sensing performance. The response of the Er1/3Yb1/3La1/3FeO3sensor toward 10 ppm butanone is enhanced to 21.3 under the applied magnetic field of 680 mT, which improves the selectivity toward butanone. This work provides a novel material design strategy for the detection of VOCs and a feasible magnetic field-assisted approach for optimizing the gas-sensing performance of perovskite ferrite materials.
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