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中国化学会首届全国磷化学学术讨论会于1988年5月30日至6月2日在北京召开。此次会议是由中国化学会主办,中国人民解放军总参防化部、防化指挥工程学院和防化研究院负责组织筹办。来自全国十 相似文献
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We have successfully grown an arsenopyrite marcasite type RhSb2 single crystal, and systematically investigated its crystal structure, electrical transport, magnetic susceptibility, heat capacity, and thermodynamic properties. We found that the temperature-dependent resistivity exhibits a bad metal behavior with a board peak around 200 K. The magnetic susceptibility of RhSb2 shows diamagnetism from 300 K to 2 K. The low-temperature specific heat shows a metallic behavior with a quite small electronic specific-heat coefficient. No phase transition is observed in both specific heat and magnetic susceptibility data. The Hall resistivity measurements show that the conduction carriers are dominated by electrons with ne = 8.62 × 1018 cm-3 at 2 K, and the electron carrier density increases rapidly above 200 K without change sign. Combining with ab-initio band structure calculations, we showed that the unusual peak around 200 K in resistivity is related to the distinct electronic structure of RhSb_2. In addition, a large thermopower S(T) about -140 μV/K is observed around 200 K, which might be useful for future thermoelectric applications. 相似文献
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LaOsSi3 single crystals are synthesized for the first time by an arc melting method. The crystal features a tetrag- onal BaNiSn3-type structure (space group 14mm) which lacks inversion symmetry along the crystallographic c axis and is isostructural with the intensively studied Rashba-type noncentrosymmetric superconductors LaRhSi3 and LaIrSi3. Un- like LaRhSi3 and LaIrSi3 displaying superconductivity, LaOsSi3 shows only metallic behavior over the measured temper- ature range of 2 K-300 K. The Sommerfeld coefficient ]/derived from specific heat is 5.76 mJ.mol-1 -K-2, indicating that LaOsSi3 has a weak electronic correlation effect. The absence of superconductivity in LaOsSi3 may lie in the Os 5d bands in the electronic structure. If it is true, it would be useful to provide complementary knowledge in understanding the relation between conduction and the d bands of M in LaMSi3 compounds (M = transition metals). 相似文献
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High quality single crystal CaFe4 As3 was grown by using the Sn flux method. Unlike layered CaFe2 As2 , CaFe4 As3 crystallizes in an orthorhombic three-dimensional structure. Two magnetic ordering transitions are observed at ~ 90 K and ~ 27 K, respectively. The high temperature transition is an antiferromagnetic(AF) ordering transition. However, the low temperature transition shows complex properties. It shows a ferromagnetic-like transition when a field is applied along b-axis, while antiferromagnetism-like transition when a field is applied perpendicular to b-axis. These results suggest that the low temperature transition at 27 K is a first-order transition from an AF state to a canted AF state. In addition, the low temperature electron specific heat coefficient reaches as high as 143 mJ/mol·K 2 , showing a heavy fermion behavior. 相似文献
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Tri-hexagonal charge order in kagome metal CsV3Sb5 revealed by 121Sb nuclear quadrupole resonance 下载免费PDF全文
We report 121Sb nuclear quadrupole resonance(NQR)measurements on kagome superconductor CsV3Sb5 with Tc=2.5 K.121Sb NQR spectra split after a charge density wave(CDW)transition at 94 K,which demonstrates a commensurate CDW state.The coexistence of the high temperature phase and the CDW phase between 91 K and 94 K manifests that it is a first order phase transition.The CDW order exhibits tri-hexagonal deformation with a lateral shift between the adjacent kagome layers,which is consistent with 2×2×2 superlattice modulation.The superconducting state coexists with CDW order and shows a conventional s-wave behavior in the bulk state. 相似文献
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本文研究了准一维电荷密度波材料NbSe3晶须自然状态(ε=0)和受到拉伸的状态(ε>0)下在纵向磁场中的磁阻效应.温度T≤50K时,无论自然状态还是拉伸状态(ε=1.5%)都没有观察到负磁阻.但是,当温度升高到T=70K,我们观察到NbSe3晶须受到拉伸至ε=1.5%时有负磁阻效应;进一步增大ε至1.8%,负磁阻效应更明显;不拉伸(ε=0)则没有磁阻.文中就这个现象进行了讨论. 相似文献
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A novel and simple atomic mirror composed of a blue-detuned semi-Gaussian beam is proposed.From the Fresnel diffraction theory,the intensity distributions of a collimated Gaussian laser beam diffracted by the straight edge of a semi-infinite opaque plate are studied.The optical potential of the semi-Gaussian beam for 85Rb atoms and its spontaneous emission probability are calculated and compared with the performance of the evanescent-wave mirror.Our study shows that the blue-detuned semi-Gaussian beam,as a novel atomic mirror,can be used to reflect atomic beam efficiently,and under the same beam parameters and lower normal atomic velocity,the performance of the semi-Gaussian-beam mirror is better than that of the evanescent-wave mirror. 相似文献
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研究了典型的层状钙钛矿结构超导单晶Sr2RuO4在c方向的磁阻(Δρ/ρ0)(H∥ab,J∥c)的变化.实验发现,磁阻表现出强烈的各向异性,并且随着温度T的降低,磁阻效应越明显;当在平面ab内旋转磁场H的方向时,磁阻成周期性变化;实验表明,磁场沿(110)方向时,出现磁阻的极大值.分别从Sr2RuO4的费米面的各向异性、载流子散射率、c方向能带色散的各向异性等方面来解释这些输运性质.
关键词:
2RuO4')" href="#">Sr2RuO4
磁阻 相似文献