Topic
Nuclear quadrupole resonance
About: Nuclear quadrupole resonance is a research topic. Over the lifetime, 3531 publications have been published within this topic receiving 38801 citations. The topic is also known as: Nuclear quadrupole resonance spectroscopy & NQR.
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02 Dec 2005TL;DR: In this paper, a method for improving the performance of a nuclear quadrupole resonance detection system by reducing the coupling between one or more excitation coils that provide a radio frequency magnetic field that excites quadrupoles nuclei, and one/more high temperature superconductor receive coils that detect the resulting nuclear quadrapole resonance signal was proposed.
Abstract: This invention relates to a method for improving the performance of a nuclear quadrupole resonance detection system by reducing the coupling between one or more excitation coils that provide a radio frequency magnetic field that excites quadrupole nuclei, and one or more high temperature superconductor receive coils that detect the resulting nuclear quadrupole resonance signal.
12 citations
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TL;DR: The hydrogen bond dynamics of pseudo-one-dimensional CsH2PO4 has been studied in the paraelectric and ferroelectric phases by 17O-proton nuclear double resonance spectroscopy as discussed by the authors.
Abstract: The hydrogen bond dynamics of pseudo‐one‐dimensional CsH2PO4 has been studied in the paraelectric and ferroelectric phases by 17O–proton nuclear double resonance spectroscopy. The results show that the protons in the short one‐dimensionally linked O–H(2)‐‐O hydrogen bonds are moving between two equilibrium sites above Tc and freeze into one of the two off‐center sites below Tc. The protons in the asymmetric O–H(1)‐‐O bonds are static and ordered in the same way both above and below Tc and seem to play only a minor role in the transition mechanism.
12 citations
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TL;DR: In this article, the authors show that the magnetic Cu moments exist only at the Cu-O pyramidal site with the 3 d 9 state and that the Cu ion at the oxygen-free plane site is nonmagnetic ( d 10 ) in the insulating Pb 2 Sr 2 RECu 3 O 8+δ.
Abstract: Nuclear magnetic resonance of 63/65 Cu in the antiferromagnetic Pb 2 Sr 2 RECu 3 O 8+δ (RE=Y, Eu and Gd) was observed in zero external field. In the insulating state with antiferromagnetically ordered Cu moments, the other set of NQR signals was observed around 30 MHz, indicating that the transferred hyperfine field from Cu moments in the Cu-O pyramids is canceled out at the Cu nuclei in the oxygen-free Cu plane site. The results show that the magnetic Cu moments exist only at the Cu-O pyramidal site with the 3 d 9 state and that the Cu ion at the oxygen-free plane site is nonmagnetic ( d 10 ) in the insulating Pb 2 Sr 2 RECu 3 O 8+δ .
12 citations
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12 citations
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TL;DR: In this article, low-energy spin fluctuations in the new filled skutterudites YbFe4Sb12 and LaFe4sb12 synthesized at high pressures were elucidated through 121Sb nuclear quadrupole resonance (NQR) and 139La NMR measurements.
Abstract: We have elucidated low-energy spin fluctuations in the new filled skutterudites YbFe4Sb12 and LaFe4Sb12 synthesized at high pressures, through 121Sb nuclear quadrupole resonance (NQR) and 139La nuclear magnetic resonance (NMR) measurements. The longitudinal spin?lattice relaxation rate 1/T1 of 121Sb in YbFe4Sb12 provides evidence that upon cooling below ~20?K, the compound transforms from the localized 4f electron state of Yb3+ ions to a nonmagnetic heavy Fermi liquid state, originating from the mixing of 4f electrons with conduction electrons. Whereas, the Curie?Weiss type behaviour of the 139La Knight shift and 121Sb- 1/T1 in LaFe4Sb12 indicate that the compound remains in the localized electron state down to 1.4?K, it in fact originates from 3d electrons of Fe in [Fe4Sb12 ] anions. In both compounds, the transversal nuclear spin?spin relaxation rate 1/T2 exhibits a clear peak at and ?K, respectively. The origin of the 1/T2 peak is discussed in terms of the freezing of the thermal vibration of Sb cages or rare-earth ions filled in each Sb cage. By comparing the experimental results of the present study with those previously reported for the compounds synthesized at ambient pressure, it is pointed out that both the strongly correlated electron properties and the thermal vibrations are greatly modified with the increase of rare-earth atom deficiency.
12 citations