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- Ji, Fuxiang, 1991-, et al.
(författare)
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Remarkable Thermochromism in the Double Perovskite Cs2NaFeCl6
- 2023
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Ingår i: Advanced Optical Materials. - : Wiley-Blackwell. - 2162-7568 .- 2195-1071.
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Tidskriftsartikel (refereegranskat)abstract
- Lead-free halide double perovskites (HDPs) have emerged as a new generation of thermochromic materials. However, further materials development and mechanistic understanding are required. Here, a highly stable HDP Cs2NaFeCl6 single crystal is synthesized, and its remarkable and fully reversible thermochromism with a wide color variation from light-yellow to black over a temperature range of 10 to 423 K is investigated. First-principles, density functional theory (DFT)-based calculations indicate that the thermochromism in Cs2NaFeCl6 is an effect of electron–phonon coupling. The temperature sensitivity of the bandgap in Cs2NaFeCl6 is up to 2.52 meVK−1 based on the Varshni equation, which is significantly higher than that of lead halide perovskites and many conventional group-IV, III–V semiconductors. Meanwhile, this material shows excellent environmental, thermal, and thermochromic cycle stability. This work provides valuable insights into HDPs' thermochromism and sheds new light on developing efficient thermochromic materials.
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| 2. |
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| 3. |
- Wan, Yan, et al.
(författare)
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The orbital effect on the anomalous magnetism and evolution in LaxY1-xVO3 (0 <= x <= 0.2) single crystals
- 2023
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 932, s. 167526-
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Tidskriftsartikel (refereegranskat)abstract
- The orbital effect on the anomalous magnetism and evolution of single crystals with low La doping, LaxY1-xVO3 (x = 0, 0.1, and 0.2), has been studied using single-crystal X-ray diffraction, specific heat, mag-netization, and Raman-scattering techniques. It is found that substituting Y3+ by La3+ increases the de-generacy of the yz/zx orbitals and decreases the Jahn-Teller distortion. These weakens the G-type (antiphase ordering along the c axis) orbital ordering phase. Meanwhile, the substituting decreases the magnetism entropy, indicating the shrinking of the t2g and eg orbital hybridization, eventually destabilizing the C-type (in-phase ordering along the c axis) antiferromagnetic ordering phase. In addition, the mechanism for the shrinking of the diamagnetism with increasing x is analyzed. It may attribute to the competition between the antisymmetric Dzyaloshinsky-Moriya interaction and the single-ion anisotropy.
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| 4. |
- Yang, Xiaoming, et al.
(författare)
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Spatial distribution of plant-available silicon and its controlling factors in paddy fields of China
- 2021
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Ingår i: Geoderma. - : Elsevier. - 0016-7061 .- 1872-6259. ; 401
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Tidskriftsartikel (refereegranskat)abstract
- Silicon (Si) is beneficial for rice health and production by alleviating various biotic and abiotic stresses. However, the continual export of grain off-farm may result in Si deficiency for rice plants. The current levels of plant available Si (PASi) in rice paddies in China remain unclear, as do the factors that control PASi content in these soils. We conducted a nationwide sampling campaign across the paddy fields of China between 2016 and 2019, and used calcium chloride extractable Si (Si-CaCl2) and buffered acetate extractable Si (Si-NaAc, pH = 4) to quantify PASi. We show that Si-CaCl2 pool was mainly influenced by mean annual temperature (MAT), soil salinity, soil organic carbon (SOC), mean annual precipitation (MAP), and soil pH, suggesting both pedological and biological control mechanisms. However, the Si-NaAc pool was influenced most by soil pH, MAT and MAP, implying pedological control. Compared to data from the 1990s, the Si-NaAc content decreased by 14.1% on a national scale with an annual decline rate of 0.54%. Based on our investigation, at least 65% of China’s paddy fields are deficient in PASi, which is an increase in area of ~15% over the last 20 years. The principal regions where PASi deficiency was recorded are mainly located in southern China, with the levels of Si deficiency lowering as the paddy fields are located further north. The continual off-site removal of PASi from rice grain and straw will need to be addressed through the use of Si-fertilizers, including organic amendments, to maintain a productive and sustainable rice industry in China.
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