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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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Book ChapterDOI
01 Jan 1978
TL;DR: The aim of the introduction is to give the general reader some perspective concerning the nature of the biological problems to which NMR techniques have been applied and how NMR can be helpful in obtaining different complementary information concerning Na+ and K+ in biological systems.
Abstract: The aim of the introduction is to give the general reader some perspective concerning the nature of the biological problems to which NMR techniques have been applied. In addition, we give a brief description of other major techniques that have been used, and point out how NMR can be helpful in obtaining different complementary information concerning Na+ and K+ in biological systems.

62 citations

Journal ArticleDOI
TL;DR: In this paper, the authors report the 75 As-NQR and NMR studies on the iron arsenide superconductor LiFeAs with T c ∼17 K. The spin lattice relaxation rate, 1/T 1 T, decreases below T c without a coherence peak, and can be fitted by gaps with s ± wave symmetry in the presence of impurity scattering.
Abstract: We report the 75 As-NQR and NMR studies on the iron arsenide superconductor LiFeAs with T c ∼17 K. The spin lattice relaxation rate, 1/ T 1 , decreases below T c without a coherence peak, and can be fitted by gaps with s ± -wave symmetry in the presence of impurity scattering. In the normal state, both 1/ T 1 T and the Knight shift decrease with decreasing temperature but become constant below T ≤50 K. Estimate of the Korringa ratio shows that the spin correlations are weaker than those in other families of iron arsenides, which may account for the lower T c in this material.

62 citations

Journal ArticleDOI
TL;DR: In this article, the complicated La-spectrum in La 2 CuO 4 shows details of the Cu-antiferromagnetism in this material which is absent in the Sr-doped, superconducting sample.

62 citations

Journal ArticleDOI
TL;DR: In this paper, the authors studied the Zeeman effect of the nuclear quadrupole spectrum for spin I=32 in crystalline powder and showed that, in a nonaxial electric field gradient, the absorption line should be broadened with a characteristic envelope by a weak static magnetic field.
Abstract: The Zeeman effect of the nuclear quadrupole resonance spectrum for spin I=32 in crystalline powder has been studied. Theoretical considerations have predicted that, in a nonaxial electric field gradient, the absorption line should be broadened with a characteristic envelope by a weak static magnetic field. When a radio‐frequency (rf) field is applied parallel to the static field, one pair of sharp minima should be produced on the envelope at the frequencies shifted by ±γH/2π from the unperturbed quadrupole resonance line, and two pairs of sharp maxima at ±(1−η)γH/2π and at ±(1+η)γH/2π. Resonance spectra of Cl35 nuclei in p‐dichlorobenzene and cyanuryl chloride have clearly displayed the predicted shape of envelopes on a recorder at room temperature. Analysis of them has resulted in determining the asymmetry parameters of electric field gradients with considerable accuracy; 0.070±0.01 for the α‐modification of p‐dichlorobenzene, and 0.22±0.03 for ν1 line, and 0.23±0.04 for ν2 line of cyanuryl chloride.

61 citations

Journal ArticleDOI
TL;DR: In this paper, the electronic and magnetic properties of La 2- x Ba x CuO 4 between 1.5 and 240 K were studied in a NQR of 139 La and they showed that the internal fields at La sites due to magnetic order largely decrease with Ba concentration.
Abstract: Nuclear quadrupole resonance (NQR) of 139 La has been performed to study the electronic and magnetic properties of La 2- x Ba x CuO 4 between 1.5 and 240 K. The temperature dependence of the separation of the double peaks in spectra clearly indicates the magnetic ordering in the small x region. The internal fields at La sites due to magnetic order largely decrease with Ba concentration. The divergence of 1/ T 2 indicates that another phase appears at low temperatures. The electric field gradient changes on passing from the normal to the superconducting states, indicating the apparent influence of superconductivity on the electronic state at La sites in this system.

61 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202320
202237
202116
202036
201928
201829