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.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, a theory is developed to connect the NQR parameters to the torsional vibrations of the N${\mathrm{O}}_{2}^{\ensuremath{-}}$ ions as well as to the order-disorder reorientational fluctuations driving the transitions.
Abstract: $^{14}\mathrm{N}$ nuclear quadrupole resonance and relaxation measurements in NaN${\mathrm{O}}_{2}$ around the ferroelectric transitions have been performed by pulse and Fourier-transform technique, with high-temperature resolution and accuracy In the narrow temperature range in which the antiferroelectric phase exists and where previous authors failed to detect the nuclear-quadrupole-resonance (NQR) signals, the splitting of the ${\ensuremath{
u}}_{+}$ and ${\ensuremath{
u}}_{\ensuremath{-}}$ lines in two components were observed A theory is developed to connect the NQR parameters to the torsional vibrations of the N${\mathrm{O}}_{2}^{\ensuremath{-}}$ ions as well as to the order-disorder reorientational fluctuations driving the transitions The critical fluctuations are described through a kinematical Ising model It is proven that the reorientational order-disorder variable is reversed by an angle which is not exactly $\ensuremath{\pi}$ By analyzing the experimental results in the light of the theoretical treatment interesting information on the critical dynamics is obtained
25 citations
TL;DR: In this paper, the results of 121,123 Sb-nuclear quadrupole resonance (NQR) and 139 La-NMR measurements on a filled skutterudite antimonide LaFe 4 Sb 12 were reported.
Abstract: We report the results of 121,123 Sb-nuclear quadrupole resonance (NQR) and 139 La-NMR measurements on a filled skutterudite antimonide LaFe 4 Sb 12 in order to investigate the magnetic properties at low temperatures from a microscopic point of view. The nuclear spin–lattice relaxation time T 1 of Sb nuclei deviates from the relation T 1 T = constant above 4.2 K, where 1/ T 1 T has a Curie–Weiss temperature dependence 1/ T 1 T = C /( T +θ) with θ∼30 K. The temperature dependence of the Knight shift of 139 La nuclei, which is related to the susceptibility at q = 0, is scaled to that of 1/ T 1 T above 40 K. This relation strongly suggests that ferromagnetic fluctuations are predominant in LaFe 4 Sb 12 . We also point out that LaFe 4 Sb 12 is situated close to the ferromagnetic instability due to the small Weiss temperature in the Curie–Weiss behavior of 1/ T 1 T and the Knight shift.
25 citations
TL;DR: In this paper, the phase transitions in Cu3SbS3 were investigated under temperature variation using X-ray diffraction and nuclear quadrupole resonance (NQR).
25 citations
TL;DR: In this paper, the theoretical and practical aspects of using multi-pulse spin-locking and the SORC sequence for detecting nitrogenated substances by the nuclear quadrupole resonance method were studied.
Abstract: Theoretical and practical aspects of using multi-pulse spin-locking and the “strong off-resonant comb” (SORC) sequence for detecting nitrogenated substances by the nuclear quadrupole resonance method were studied. A number of optimum correlations between the parameters of multi-pulse sequences and the relaxation characteristics of the substances under investigation were determined. The obtained relations were used for the fast detection of α-trinitrotoluene (TNT). Relaxation parameters and temperature coefficients for twelve 14N lines of the orthorhombic phase of TNT measured at room temperature are also presented. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
25 citations
TL;DR: Results and broadening of the NQR spectrum at low temperatures indicate that slow charge fluctuations of either electronic or ionic origin freeze gradually atLow temperatures.
Abstract: We report nuclear quadrupole resonance (NQR) studies on the chain Cu sites of PrBa 2 Cu 4 O 8 , a quasi-one-dimensional conductor with a nearly quarter-filled band The nuclear spin-lattice relaxation rate 1/T 1 shows a pronounced peak near 100 K caused by fluctuations of electric field gradient Similar peak was observed for the spin-echo decay rate 1/T 2 , however, at a different temperature near 50 K These results and broadening of the NQR spectrum at low temperatures indicate that slow charge fluctuations of either electronic or ionic origin freeze gradually at low temperatures
25 citations