To make the ferroelectric BaTiO3 possess ferromagnetism simultaneously,magnetic Fe was doped into BaTiO3 ceramics at doping levels up to 10%(molar fraction).Both tetragonal and hexagonal phases coexisted in the Fe-dop...To make the ferroelectric BaTiO3 possess ferromagnetism simultaneously,magnetic Fe was doped into BaTiO3 ceramics at doping levels up to 10%(molar fraction).Both tetragonal and hexagonal phases coexisted in the Fe-doped BaTiO3 ceramics except at 1% doping level.X-ray diffraction analysis indicated that higher doping level of Fe,higher sintering temperature and longer sintering time promoted the formation of hexagonal phases in Fe-doped BaTiO3 ceramics.Ferroelectricity was observed in all samples at room temperature,but it was greatly depressed by Fe doping.Except at doping level of 1%,room-temperature ferromagnetism was observed in the BaTiO3 ceramics.The dependence of the saturation magnetization and coercivities of the Fe-doped BaTiO3 ceramics on doping level was systematically studied.Both the saturation magnetization and magnetic coercivities were found to be dependent on the doping level as well as the fraction of the hexagonal phase in the ceramics.展开更多
The Major ana zero mode(MZM), which manifests as an exotic neutral excitation in superconductors, is the building block of topological quantum computing. It has recently been found in the vortices of several iron-base...The Major ana zero mode(MZM), which manifests as an exotic neutral excitation in superconductors, is the building block of topological quantum computing. It has recently been found in the vortices of several iron-based superconductors as a zero-bias conductance peak in tunneling spectroscopy. In particular, a clean and robust MZM has been observed in the cores of free vortices in(Li_(0.84)Fe_(0.16))OHFeSe. Here using scanning tunneling spectroscopy, we demonstrate that Major ana-induced resonant Andreev reflection occurs between the STM tip and this zero-bias bound state,and consequently, the conductance at zero bias is quantized as 2e^2/h. Our results present a hallmark signature of the MZM in the vortex of an intrinsic topological superconductor, together with its intriguing behavior.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
The effect of heat treatment mode on the microstructure of Fe-Cr-B cast iron alloys was investigated inthis paper by comparing the difference of precipitation patterns of secondary particles after thermal cycling trea...The effect of heat treatment mode on the microstructure of Fe-Cr-B cast iron alloys was investigated inthis paper by comparing the difference of precipitation patterns of secondary particles after thermal cycling treatment(TCT) with those after normal heat treatment (NHT). No obvious differences were found in precipitation patterns ofsecondary particles between TCT and NHT when experimental temperature was below Ar1. However, whentemperature was over Ar1, there were significant differences, with secondary particles prominently segregated at thegrain boundaries under TCT, while the particles evenly distributed in the matrix under NHT. The reason for themicrostructure differences could be associated with the development of non-equilibrium segregation of boron duringTCT.展开更多
Switchable diode effect in ferroelectric diodes has attracted much attention for its potential applications in novel nonvolatile memories. We briefly review recent investigations on the switchable diode effect in ferr...Switchable diode effect in ferroelectric diodes has attracted much attention for its potential applications in novel nonvolatile memories. We briefly review recent investigations on the switchable diode effect in ferroelectric diodes both experimentally and theoretically. Many recent studies demonstrate that the interfacial barrier between the metal-ferroelectrics could be modulated by the polarization charges, and the ferroelectric polarization that can be reversed by an external electric field plays a dominant role in the switchable diode effect. Moreover, we review a self-consistent numerical model, which can well describe the switchable diode effect in ferroelectric diodes. Based on this model, it can be predicted that it is a better choice to select metals with a smaller permittivity, such as noble metals, to obtain a more pronounced switchable diode effect in ferroelectric diodes.展开更多
Ferroelectric and magnetic properties of Fe1-xMnxV2O4 （0 ≤ x ≤ 0.5） spinels are investigated on the basis of dielectric, polarization, and susceptibility measurements. Ferroeleetric polarization is discovered in c...Ferroelectric and magnetic properties of Fe1-xMnxV2O4 （0 ≤ x ≤ 0.5） spinels are investigated on the basis of dielectric, polarization, and susceptibility measurements. Ferroeleetric polarization is discovered in collinear ferrimagnetic and Yafet-Kittel magnetic phases for 0.1 ≤ x ≤ 0.4, which can be tuned by a magnetic field. As orbital-active FJ＋ is substituted with Mn2＋, ferroeleetric polarization decreases for 0 ≤ x ≤ 0.4 and disappears for x=0.5. We propose that the two polar components in ferroelectric polarization originate from the exchange striction mechanism and the spin-current model, respectively.展开更多
基于不同氧化物与碳的结合能不同,与碳的还原反应在不同的分析条件下具有先后次序,用脉冲红外氧化物夹杂分析仪,对4μm的烧结Nd Fe B永磁材料粉末的氧化行为进行了方法研究。实验结果表明,通过合理设置参数,选用跟踪升温模式,可以快速分...基于不同氧化物与碳的结合能不同,与碳的还原反应在不同的分析条件下具有先后次序,用脉冲红外氧化物夹杂分析仪,对4μm的烧结Nd Fe B永磁材料粉末的氧化行为进行了方法研究。实验结果表明,通过合理设置参数,选用跟踪升温模式,可以快速分离Nd Fe B永磁材料粉末中的不同氧化物,并可以通过加权方法进行定性验证。展开更多
通过10 kg感应炉研究了Ca-Si线与FeS加入次序对低碳结构钢(/%:0.16C,0.65Mn,0.25Si,0.034S,0.025P)硫化物形貌和切削性能的影响。以钢中非金属夹杂物变形处理为基础,采用Image Pro Plus软件对钢中夹杂物指标进行定量分析,得出采用先加入...通过10 kg感应炉研究了Ca-Si线与FeS加入次序对低碳结构钢(/%:0.16C,0.65Mn,0.25Si,0.034S,0.025P)硫化物形貌和切削性能的影响。以钢中非金属夹杂物变形处理为基础,采用Image Pro Plus软件对钢中夹杂物指标进行定量分析,得出采用先加入Ca-Si线后加FeS的合金化模式时,钢中夹杂物平均长度为12.3μm,单位面积上条状夹杂物与粒状夹杂物之比为64:41,而采用先加FeS后加Ca-Si线的合金化模式,钢中夹杂物平均长度为9.9μm,单位面积条状夹杂物与粒状夹杂物数量之比为52:53,且钢样的切削性能较先加Ca-Si线模式好,因此先加FeS后加Ca-Si线的合金化工艺有利于控制钢中硫化物形态。展开更多
基金Project(60661001) supported by the National Natural Science Foundation of China
文摘To make the ferroelectric BaTiO3 possess ferromagnetism simultaneously,magnetic Fe was doped into BaTiO3 ceramics at doping levels up to 10%(molar fraction).Both tetragonal and hexagonal phases coexisted in the Fe-doped BaTiO3 ceramics except at 1% doping level.X-ray diffraction analysis indicated that higher doping level of Fe,higher sintering temperature and longer sintering time promoted the formation of hexagonal phases in Fe-doped BaTiO3 ceramics.Ferroelectricity was observed in all samples at room temperature,but it was greatly depressed by Fe doping.Except at doping level of 1%,room-temperature ferromagnetism was observed in the BaTiO3 ceramics.The dependence of the saturation magnetization and coercivities of the Fe-doped BaTiO3 ceramics on doping level was systematically studied.Both the saturation magnetization and magnetic coercivities were found to be dependent on the doping level as well as the fraction of the hexagonal phase in the ceramics.
基金Supported by the National Natural Science Foundation of Chinathe National Key R&D Program of China under Grant Nos2016YFA0300200,2017YFA0303004 and 2017YFA0303003the Key Research of Frontier Sciences of CAS under Grant No QYZDY-SSW-SLH001
文摘The Major ana zero mode(MZM), which manifests as an exotic neutral excitation in superconductors, is the building block of topological quantum computing. It has recently been found in the vortices of several iron-based superconductors as a zero-bias conductance peak in tunneling spectroscopy. In particular, a clean and robust MZM has been observed in the cores of free vortices in(Li_(0.84)Fe_(0.16))OHFeSe. Here using scanning tunneling spectroscopy, we demonstrate that Major ana-induced resonant Andreev reflection occurs between the STM tip and this zero-bias bound state,and consequently, the conductance at zero bias is quantized as 2e^2/h. Our results present a hallmark signature of the MZM in the vortex of an intrinsic topological superconductor, together with its intriguing behavior.
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.
文摘The effect of heat treatment mode on the microstructure of Fe-Cr-B cast iron alloys was investigated inthis paper by comparing the difference of precipitation patterns of secondary particles after thermal cycling treatment(TCT) with those after normal heat treatment (NHT). No obvious differences were found in precipitation patterns ofsecondary particles between TCT and NHT when experimental temperature was below Ar1. However, whentemperature was over Ar1, there were significant differences, with secondary particles prominently segregated at thegrain boundaries under TCT, while the particles evenly distributed in the matrix under NHT. The reason for themicrostructure differences could be associated with the development of non-equilibrium segregation of boron duringTCT.
基金supported by the National Basic Research Program of China (Nos. 2012CB921403 and 2013CB328706)the National Natural Science Foundation of China (Nos. 11134012 and 11174355)
文摘Switchable diode effect in ferroelectric diodes has attracted much attention for its potential applications in novel nonvolatile memories. We briefly review recent investigations on the switchable diode effect in ferroelectric diodes both experimentally and theoretically. Many recent studies demonstrate that the interfacial barrier between the metal-ferroelectrics could be modulated by the polarization charges, and the ferroelectric polarization that can be reversed by an external electric field plays a dominant role in the switchable diode effect. Moreover, we review a self-consistent numerical model, which can well describe the switchable diode effect in ferroelectric diodes. Based on this model, it can be predicted that it is a better choice to select metals with a smaller permittivity, such as noble metals, to obtain a more pronounced switchable diode effect in ferroelectric diodes.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CB921904 and 2012CB927402the National Natural Science Foundation of China under Grant Nos 11074142 and 11021464+1 种基金the Key Project of the Ministry of Education of China under Grant No 309003the Tsinghua TNList Cross-discipline Foundation
文摘Ferroelectric and magnetic properties of Fe1-xMnxV2O4 （0 ≤ x ≤ 0.5） spinels are investigated on the basis of dielectric, polarization, and susceptibility measurements. Ferroeleetric polarization is discovered in collinear ferrimagnetic and Yafet-Kittel magnetic phases for 0.1 ≤ x ≤ 0.4, which can be tuned by a magnetic field. As orbital-active FJ＋ is substituted with Mn2＋, ferroeleetric polarization decreases for 0 ≤ x ≤ 0.4 and disappears for x=0.5. We propose that the two polar components in ferroelectric polarization originate from the exchange striction mechanism and the spin-current model, respectively.
文摘基于不同氧化物与碳的结合能不同,与碳的还原反应在不同的分析条件下具有先后次序,用脉冲红外氧化物夹杂分析仪,对4μm的烧结Nd Fe B永磁材料粉末的氧化行为进行了方法研究。实验结果表明,通过合理设置参数,选用跟踪升温模式,可以快速分离Nd Fe B永磁材料粉末中的不同氧化物,并可以通过加权方法进行定性验证。
文摘通过10 kg感应炉研究了Ca-Si线与FeS加入次序对低碳结构钢(/%:0.16C,0.65Mn,0.25Si,0.034S,0.025P)硫化物形貌和切削性能的影响。以钢中非金属夹杂物变形处理为基础,采用Image Pro Plus软件对钢中夹杂物指标进行定量分析,得出采用先加入Ca-Si线后加FeS的合金化模式时,钢中夹杂物平均长度为12.3μm,单位面积上条状夹杂物与粒状夹杂物之比为64:41,而采用先加FeS后加Ca-Si线的合金化模式,钢中夹杂物平均长度为9.9μm,单位面积条状夹杂物与粒状夹杂物数量之比为52:53,且钢样的切削性能较先加Ca-Si线模式好,因此先加FeS后加Ca-Si线的合金化工艺有利于控制钢中硫化物形态。
