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Ferroelectric behaviour of 30nm BaTiO3 ceramics prepared by high pressure assisted sintering 下载免费PDF全文
Dense nanocrystalline BaTiO3 ceramics with a homogeneous grain size of 30 nm was obtained by pressure assisted sintering. The ferroelectric behaviour of the ceramics was characterized by the dielectric peak at around 120 ℃, the P-E hysteresis loop and some ferroelectric domains. These experimental results indicate that the critical grain size for the disappearance of ferroelectricity in nanocrystalline BaTiO3 ceramics fabricated by pressure assisted sintering is below 30 nm. The ferroelectric property decreasing with decreasing grain size can be explained by the lowered tetragonality and the 'dilution' effect of grain boundaries. 相似文献
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以右旋丙交酯(D-LA)和对二氧环己酮(PDO)为原料,辛酸亚锡为催化剂,采用本体聚合方法合成了不同配比的共聚物(PDLA-co-PPDO-1~ PDLA-co-PPDO-3),其结构和性能经1H NMR和DSC等表征。结果表明:聚合物的重均分子量依次为97258、 60372和23284。随着PDO组分增加,共聚物分子量降低;玻璃化转变温度Tg为50 ℃,熔融温度为135 ℃左右;共聚物接触角为70~80°,具有一定疏水性;聚合物于135 ℃等温结晶,7 min后球晶不再生长,结晶速率较快。 相似文献
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Effects of pressure and/or magnetism on the critical superconducting temperature(Tc)ofδ-Mo N single crystal were investigated using a Maglab system.Theδ-Mo N single crystal was synthesized at extreme conditions of high pressure and high temperature.The carrier density ofδ-Mo N single crystal as a function of applied pressure was determined using Hall coefficient measurement. 相似文献
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Structure-Spin-Transport Anomaly in Quasi-One-Dimensional Ba_9Fe_3Te_(15) under High Pressure 下载免费PDF全文
Recently, a series of novel compounds Ba3MX5(M = Fe, Ti, V; X = Se, Te) with hexagonal crystal structures composed of quasi-1-dimensional(1D) magnetic chains has been synthesized by our research team using high-pressure and high-temperature methods. The initial hexagonal phases persist to the maximum achievable pressure, while spin configurations and magnetic interactions may change dramatically as a result of considerable reductions in interchain separations upon pressuriz... 相似文献
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We investigate the temperature dependence of the dielectric constant of BaTiO3 ceramic with coarse to nanograin size under different hydrostatic high pressures up to 5000 bar in the range between room temperature and 200℃. The ferroelectric-to-paraelectric phase transition temperatures Tc are determined from the peak of dielectric constant versus temperature. The values of average grain-size are estimated from the SEM images. It is found that the magnitude of dTc/dp varies considerably from sample to sample depending on grain size. The Curie point Tc of the sample with small grain size decreases more sharply than that of samples with larger one. 相似文献
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Structural stability at high pressure,electronic, and magnetic properties of BaFZnAs:A new candidate of host material of diluted magnetic semiconductors 下载免费PDF全文
The layered semiconductor BaFZnAs with the tetragonal ZrCuSiAs-type structure has been successfully synthesized.Both the in-situ high-pressure synchrotron x-ray diffraction and the high-pressure Raman scattering measurements demonstrate that the structure of BaFZnAs is stable under pressure up to 17.5 GPa at room temperature. The resistivity and the magnetic susceptibility data show that BaFZnAs is a non-magnetic semiconductor. BaFZnAs is recommended as a candidate of the host material of diluted magnetic semiconductor. 相似文献
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何鑫 张昌玲 李芷文 张思佳 闵保森 张俊 卢可 赵建发 史鲁川 彭毅 望贤成 冯少敏 宋静 王鲁红 V.B.Prakapenka S.Chariton 刘浩哲 靳常青 《中国物理快报》2023,(5):135-138
We report experimental discovery of tantalum polyhydride superconductor.It was synthesized under highpressure and high-temperature conditions using diamond anvil cell combined with in situ high-pressure laser heating techniques.The superconductivity was investigated via resistance measurements at pressures.The highest superconducting transition temperature Tc was found to be ~30 K at 197 GPa in the sample that was synthesized at the same pressure with ~2000 K heating.The transitions a... 相似文献
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