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 double nuclear resonance technique was employed to calculate the electric field gradient and the anisotropy constant for five distinct nitrogen sites in the series and the results obtained are shown to be consistent with molecular orbital calculations on these compounds.
21 citations
TL;DR: The nuclear quadrupole resonance spectrum of bromine was detected and measured in TiBr/sub 4/ as mentioned in this paper, where the temperature dependence of the resonance frequencies was determined from data points obtained between 77 deg K and room temperature.
Abstract: The nuclear quadrupole resonance spectrum of bromine was detected and measured in TiBr/sub 4/. The temperature dependence of the resonance frequencies was determined from data points obtained between 77 deg K and room temperature. In addition, the pressure dependence at room temperature to 10,000 psi was determined. The resonance frequency depends on pressure through direct volume dependence of the field gradients, and through the volume dependence of the vibration amplitudes which in turn average the field gradients. (J.R.D.)
21 citations
TL;DR: A series of copper minerals has been investigated by NQR (Nuclear Quadrupole Resonance), the most typical cases of Cu(I) environment in oxides, sulphides and sulphosalts being taken into account as mentioned in this paper.
Abstract: A series of copper minerals has been investigated by NQR (Nuclear Quadrupole Resonance), the most typical cases of Cu(I) environment in oxides, sulphides and sulphosalts being taken into account. The linear complexes CuX2 have the greatest quadrupole splitting. Minimal quadrupole splitting is observed in tetrahedral complexes. Spin-lattice relaxation measurements indicate that the quadrupole relaxation mechanism due to the Raman process predominates.
21 citations
TL;DR: In this article, the nuclear quadrupole resonance (NQR) of Cu in the spin-Peierls system CuGeO 3 has been observed at 34.23±0.02 MHz for 63 Cu and 31.66± 0.2 MHz for 65 Cu at 4.2 K under zero external field.
Abstract: We have observed the nuclear quadrupole resonance (NQR) of Cu in the spin-Peierls system CuGeO 3 . The NQR signals have been observed at 34.23±0.02 MHz for 63 Cu and 31.66±0.02 MHz for 65 Cu at 4.2 K under zero external field. These signals persist down to 1.3 K with neither line splitting nor broadening due to the internal magnetic field. This fact indicates there is no long-range order of Cu spins. The 63 Cu nuclear spin-lattice relaxation rate 63 (1/ T 1 ) rapidly drops below 15 K which clearly demonstrates an opening of the energy gap in the excitation spectrum. However, no anomaly was detected in the Cu NQR frequency at the transition temperature. It was also found that 63 (1/ T 1 ) above 15 K smoothly extrapolates to a finite value at 0 K. This may suggest the spin dynamics in the paramagnetic state is described in terms of the one-dimensional antiferromagnetic Heisenberg model with S =1/2.
21 citations
TL;DR: In this article, the gap magnitude of 70 K with a mid-gap state of 42% is estimated based on a rectangular density of states, which suggests that CeFe 2 Al 10 is a Kondo semiconductor with a kondo temperature much higher than 300 K.
Abstract: 27 Al-NQR/NMR measurements have been performed on CeFe 2 Al 10 in relevance to the novel phase below T 0 =27 K of isostructural CeRu 2 Al 10 . NQR peaks are assigned to five crystallographically inequivalent Al sites. No splitting of the NQR spectra down to 1.5 K confirms the lack of phase transition in this compound. The gaplike decrease in the spin–lattice relaxation rate 1/ T 1 above about 20 K, following the Korringa law ( T 1 T = const.) below 20 K, indicates a pseudogap opening near the Fermi level. The gap magnitude of 70 K with a mid-gap state of 42% is estimated based on a rectangular density of states. The gap magnitude is much larger than the gap of 15 K evaluated previously from the electrical resistivity, which suggests CeFe 2 Al 10 to be a Kondo semiconductor with a Kondo temperature much higher than 300 K.
21 citations