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We provide experimental evidence of higher multipole (magnetic dipole and electric quadrupole) radiation in second-harmonic (SH) generation from arrays of metal nanoparticles. Fundamental differences in the radiative properties of electric dipoles and higher multipoles yield opposite interference effects observed in the SH intensities measured in the reflected and transmitted directions. These interference effects clearly depend on the polarization of the fundamental field, directly indicating the importance of multipole effects in the nonlinear response. We estimate that higher multipoles contribute up to 20% of the total emitted SH field amplitude for certain polarization configurations. 相似文献
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Volodymyr Gvozdetskyi Michael P. Hanrahan Raquel A. Ribeiro Tae-Hoon Kim Lin Zhou Aaron J. Rossini Paul C. Canfield Julia V. Zaikina 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4123-4135
Ternary lithium nickel borides LiNi3B1.8 and Li2.8Ni16B8 have been synthesized by using reactive LiH as a precursor. This synthetic route allows better mixing of the precursor powders, thus facilitating rapid preparation of the alkali-metal-containing ternary borides. This method is suitable for “fast screening” of multicomponent systems comprised of elements with drastically different reactivities. The crystal structures of the compounds LiNi3B1.8 and Li2.8Ni16B8 have been re-investigated by a combination of single-crystal X-ray/synchrotron powder diffraction, solid-state 7Li and 11B NMR spectroscopies, and scanning transmission electron microscopy. This has allowed the determination of fine structural details, including the split position of Ni sites and the ordering of B vacancies. Field-dependent and temperature-dependent magnetization measurements are consistent with spin-glass behavior for both samples. 相似文献
136.
P.C. Canfield S.L. Bud’ko N. Ni A. Kreyssig A.I. Goldman R.J. McQueeney M.S. Torikachvili D.N. Argyriou G. Luke W. Yu 《Physica C: Superconductivity and its Applications》2009,469(9-12):404-412
At ambient pressure CaFe2As2 has been found to undergo a first order phase transition from a high temperature, tetragonal phase to a low-temperature orthorhombic/antiferromagnetic phase upon cooling through T ~ 170 K. With the application of pressure this phase transition is rapidly suppressed and by ~0.35 GPa it is replaced by a first order phase transition to a low-temperature collapsed tetragonal, non-magnetic phase. Further application of pressure leads to an increase of the tetragonal to collapsed tetragonal phase transition temperature, with it crossing room temperature by ~1.7 GPa. Given the exceptionally large and anisotropic change in unit cell dimensions associated with the collapsed tetragonal phase, the state of the pressure medium (liquid or solid) at the transition temperature has profound effects on the low-temperature state of the sample. For He-gas cells the pressure is as close to hydrostatic as possible and the transitions are sharp and the sample appears to be single phase at low temperatures. For liquid media cells at temperatures below media freezing, the CaFe2As2 transforms when it is encased by a frozen media and enters into a low-temperature multi-crystallographic-phase state, leading to what appears to be a strain stabilized superconducting state at low temperatures. 相似文献
137.
P. Samuely Z. Pribulová P. Szabó G. Pristá? S.L. Bud’ko P.C. Canfield 《Physica C: Superconductivity and its Applications》2009,469(9-12):507-511
A brief overview of the superconducting energy gap studies on 122-type family of iron pnictides is given. It seems that the situation in the hole doped Ba1?xKxFe2As2 is well resolved. Most of the measurements including the presented here point contact Andreev reflection spectra agree on existence of multiple nodeless gaps in the excitation spectrum of this multiband system. The gaps have basically two sizes – the small one with a strength up to the BCS weak coupling limit and the large one with a very strong coupling with 2ΔL/kTc > 6–8. In the electron doped Ba(Fe1?xCox)2As2 the most of the experiments including our point contact measurements reveal in quite broadened spectra only a single gap with a strong coupling strength. The high precision ARPES measurements on this system identified two gaps but very close to each other, both showing a strong coupling with 2Δ/kTc ~ 5 and 6, respectively. 相似文献
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We present a comprehensive study of the binary intermetallic superconductor, BaSn5. High-quality single crystalline BaSn5 was grown out of a Sn flux. Detailed thermodynamic and transport measurements were performed to study BaSn5's normal and superconducting state properties. This material appears to be a strongly coupled, multiband superconductor. H c2(T) is almost isotropic. De Haas–van Alphen oscillations were observed and two effective masses were estimated from the FFT spectra. Hydrostatic pressure causes a decrease in the superconducting transition temperature at the rate of ≈?0.053?±?0.001?K/kbar. 相似文献
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