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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TL;DR: In this paper, the free precession of an ensemble of nuclear quadrupole moments in an axial electric field gradient is studied by the pulsed nuclear induction method, which is analogous to the macroscopic nuclear induction equations of Bloch.
Abstract: The free precession of an ensemble of nuclear quadrupole moments in an axial electric field gradient is studied by the pulsed nuclear induction method. A quantum-mechanical analysis describes the free precession and spin echo signals which result from the application of single and double pulses of radio-frequency field at the condition of zero-field quadrupole resonance. Beat modulation effects exhibited by free precession signals in a small constant external magnetic field are predicted by analysis. An alternative semiclassical description of quadrupole precession is given, which is analogous to the macroscopic nuclear induction equations of Bloch. Theory is verified by observation of free precession signals of chlorine in NaCl${\mathrm{O}}_{3}$.
145 citations
Journal Article•
TL;DR: Pulsed NMR and NQR data for 63 Cu and 65 Cu below T c and 89 Y NMR data above T c are presented in this paper, and the results show that no magnetic ordering between 20 and 270 K; no structural change at T c ; and different Knight shifts and electric field gradients at Cu1 and Cu2 sites.
142 citations
TL;DR: It is demonstrated that atomic-like impurities in diamond can be used to probe the properties of 2D materials by nanometer-scale nuclear quadrupole resonance spectroscopy, which could enable the development of new quantum hybrid systems.
Abstract: Two-dimensional (2D) materials offer a promising platform for exploring condensed matter phenomena and developing technological applications. However, the reduction of material dimensions to the atomic scale poses a challenge for traditional measurement and interfacing techniques that typically couple to macroscopic observables. We demonstrate a method for probing the properties of 2D materials via nanometer-scale nuclear quadrupole resonance (NQR) spectroscopy using individual atomlike impurities in diamond. Coherent manipulation of shallow nitrogen-vacancy (NV) color centers enables the probing of nanoscale ensembles down to approximately 30 nuclear spins in atomically thin hexagonal boron nitride (h-BN). The characterization of low-dimensional nanoscale materials could enable the development of new quantum hybrid systems, combining atomlike systems coherently coupled with individual atoms in 2D materials.
140 citations
TL;DR: In this article, a nuclear double-resonance method was used to measure the magnetic order of abundant nuclei which are dipolar-coupled to the low-abundance nuclear species.
Abstract: The pure nuclear quadrupole resonance of a low-abundance spin species in zero field is observed for molar concentrations as low as one part in ${10}^{7}$ by the application of a nuclear-double-resonance method. The quadrupole resonance is measured in terms of a decrease in the magnetic order of abundant nuclei which are dipolar-coupled to the low-abundance nuclear species. The double-resonance process is analyzed from the point of view of two energy reservoirs coupled by a dipolar perturbation, and spin diffusion among abundant nuclei is included phenomenologically. Radio-frequency power, which causes the main quadrupole transitions of rare spins, is frequency-modulated to provide saturation in the rotating frame and to enable identification of unknown spin transitions. The pure nuclear quadrupole resonance of Na and Cl nuclei near impurities and imperfections in NaCl is measured. Particular attention is given to the resonances associated with ${\mathrm{K}}^{+}$ and ${\mathrm{Br}}^{\ensuremath{-}}$ ions injected as impurities into the NaCl lattice. An unsuccessful search in zero field has been made for the naturally abundant 0.0156% deuterium quadrupole resonance in CaS${\mathrm{O}}_{4}$\ifmmode\cdot\else\textperiodcentered\fi{}2${\mathrm{H}}_{2}$O and ${\mathrm{C}}_{10}$${\mathrm{H}}_{8}$, where the proton resonance is monitored as the abundant nuclear species. The proton dipolar absorption in zero magnetic field is anomalously broad and overlaps too much with the deuterium quadrupole resonance to permit independent observation of the latter. A narrowing of proton dipolar absorption in zero field is observed for strong radio-frequency fields larger than internal dipole fields.
128 citations
TL;DR: In this paper, the coherent evolution of nuclear spin observables in zero magnetic field with the full sensitivity of high field NMR was described and demonstrated for detecting the magnetic dipole and electric quadrupole interactions of disordered systems without the line broadening associated with random orientation with respect to the applied magnetic field.
Abstract: Methods are described and demonstrated for detecting the coherent evolution of nuclear spin observables in zero magnetic field with the full sensitivity of high field NMR. The principle motivation is to provide a means of obtaining solid state spectra of the magnetic dipole and electric quadrupole interactions of disordered systems without the line broadening associated with random orientation with respect to the applied magnetic field. Comparison is made to previous frequency domain and high field methods. A general density operator formalism is given for the experiments where the evolution period is initiated by a sudden switching to zero field and is terminated by a sudden restoration of the field. Analytical expressions for the signals are given for a variety of simple dipolar and quadrupolar systems and numerical simulations are reported for up to six coupled spin-1/2 nuclei. Experimental results are reported or reviewed for 1H, 2D, 7Li, 13C, and 27Al nuclei in a variety of polycrystalline materials. The effects of molecular motion and bodily sample rotation are described. Various extensions of the method are discussed, including demagnetized initial conditions and correlation by two-dimensional Fourier transformation of zero field spectra with themselves or with high field spectra.
126 citations