scholarly journals Spin noise gradient echoes

2021 ◽  
Vol 2 (2) ◽  
pp. 827-834
Author(s):  
Victor V. Rodin ◽  
Stephan J. Ginthör ◽  
Matthias Bechmann ◽  
Hervé Desvaux ◽  
Norbert Müller
Keyword(s):  
Field Gradient ◽  
Magnetic Field Gradient ◽  
Relaxation Times ◽  
Difference Spectra ◽  
Transverse Relaxation ◽  
Transient Phenomena ◽  
Pulsed Field ◽  
Spin Noise ◽  
Field Gradients ◽  
Noise Spectroscopy

Abstract. Nuclear spin noise spectroscopy in the absence of radio frequency pulses was studied under the influence of pulsed field gradients (PFGs) on pure and mixed liquids. Under conditions where the radiation-damping-induced line broadening is smaller than the gradient-dependent inhomogeneous broadening, echo responses can be observed in difference spectra between experiments employing pulsed field gradient pairs of the same and opposite signs. These observed spin noise gradient echoes (SNGEs) were analyzed through a simple model to describe the effects of transient phenomena. Experiments performed on high-resolution nuclear magnetic resonance (NMR) probes demonstrate how refocused spin noise behaves and how it can be exploited to determine sample properties. In bulk liquids and their mixtures, transverse relaxation times and translational diffusion constants can be determined from SNGE spectra recorded following tailored sequences of magnetic field gradient pulses.

scholarly journals Spin-Noise Gradient Echoes

2021 ◽  
Author(s):  
Victor V. Rodin ◽  
Stephan J. Ginthör ◽  
Matthias Bechmann ◽  
Hervé Desvaux ◽  
Norbert Müller
Keyword(s):  
Field Gradient ◽  
Magnetic Field Gradient ◽  
Relaxation Times ◽  
Difference Spectra ◽  
Transverse Relaxation ◽  
Transient Phenomena ◽  
Pulsed Field ◽  
Spin Noise ◽  
Field Gradients ◽  
Noise Spectroscopy

Abstract. Nuclear spin-noise spectroscopy in absence of radio frequency pulses was studied under the influence of pulsed field gradients (PFGs) on pure and mixed liquids. Under conditions, where the radiation-damping induced line broadening is smaller than the gradient dependent inhomogeneous broadening, echo responses can be observed in difference spectra between experiments employing pulsed field gradient pairs of same and opposite signs. These observed “spin-noise gradient echoes” (SNGEs) were analyzed through a simple model to describe the effects of transient phenomena. Experiments performed on high resolution NMR probes demonstrate how “refocused spin noise” behaves and how it can be exploited to determine sample properties. In bulk liquids and their mixtures transverse relaxation times as well as translational diffusion constants can be determined from SNGE spectra recorded following tailored sequences of magnetic field gradient pulses.

scholarly journals Nuclear Magnetic Resonance (NMR) Characterization of a Polymerized Ionic Liquid Electrolyte Material

2012 ◽  
Vol 1440 ◽  
Author(s):  
A.L. Michan ◽  
G.T.M. Nguyen ◽  
O. Fichet ◽  
F. Vidal ◽  
C. Vancaeyzeele ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Field Gradient ◽  
Diffusion Coefficients ◽  
Polymer Network ◽  
Relaxation Times ◽  
Solid Polymer ◽  
Pulsed Field ◽  
Nuclear Magnetic

ABSTRACTSolid electrolyte materials have the potential to improve performance and safety characteristics of lithium-ion batteries by replacing conventional solvent-based electrolytes. A candidate solid polymer electrolyte, AMLi/PEGDM, has been synthesized by crosslinking an anionic monomer AMLi, with poly(ethylene glycol) dimethacrylate. The main goal of the synthesis is to produce a single-ion conducting polymer network where lithium cations can move freely and fluorinated anions are immobilized as part of the polymer network. A comprehensive characterization of anion and cation mobility in the resulting material is therefore required. Using pulsed-field gradient nuclear magnetic resonance (PFG-NMR), we are able to measure and quantify the individual diffusion coefficients of mobile species in the material (19F and 7Li) and confirm the extent to which the fluorinated anionic component is immobilized. We have characterized dry (σ~3.0 x10-7 S/cm at 30°C) and propylene carbonate (PC) saturated gel (σ~1.0x10-4 S/cm at 30°C) samples. Experimental results include NMR spin-spin and spin-lattice relaxation times in addition to diffusion coefficient measurements over a temperature range up to 100°C. Practically, the diffusion measurements are extremely challenging, as the spin-spin (T2) relaxation times are very short, necessitating the development of specialized pulsed-field gradient apparatus. Diffusion coefficients for the most mobile components of the lithium cations and fluorinated anions at 100°C in dry membranes have been found to be 3.4 x10-8 cm2/s and 2.1 x10-8 cm2/s respectively. These results provide valuable insight into the conduction mechanisms in these materials, and will drive further optimization of solid polymer electrolytes.

Formation of p-cresol:piperazine complex in solution monitored by spin–lattice relaxation times and pulsed field gradient NMR diffusion measurements

2003 ◽  
Vol 164 (2) ◽  
pp. 197-204 ◽  
Author(s):  
Erika Martins de Carvalho ◽  
Marcia Helena Rodrigues Velloso ◽  
Luzineide Wanderley Tinoco ◽  
José Daniel Figueroa-Villar
Keyword(s):  
Field Gradient ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Pulsed Field Gradient Nmr ◽  
Pulsed Field ◽  
Spin Lattice ◽  
Nmr Diffusion

Magnetostrictive gradient in Tb0.27Dy0.73Fe1.95 induced by high magnetic field gradient applied during solidification

2016 ◽  
Vol 09 (01) ◽  
pp. 1650003 ◽  
Author(s):  
Pengfei Gao ◽  
Tie Liu ◽  
Meng Dong ◽  
Yi Yuan ◽  
Kai Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Gradient ◽  
High Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Field Gradient ◽  
Gradient Distribution ◽  
Field Gradients ◽  
Magnetic Field Gradients ◽  
The Magnetic Field

We investigated how high magnetic field gradients affected the magnetostrictive performance of Tb[Formula: see text]Dy[Formula: see text]Fe[Formula: see text] during solidification. At high applied magnetic field gradients, the magnetostriction exhibited a gradient distribution throughout the alloy. Increasing the magnetic field gradient also increased the magnetostriction gradient. We attributed the graded magnetostrictive performance to the gradient distribution of (Tb, Dy)Fe2 phase in the alloy and its orientation.

Alignment of Primary Al3Ni Phases in Hypereutectic Al-Ni Alloys with Various Compositions under High Magnetic Field Gradients

2010 ◽  
Vol 649 ◽  
pp. 165-169 ◽  
Author(s):  
Tie Liu ◽  
Qiang Wang ◽  
Zhong Ying Wang ◽  
Dong Gang Li ◽  
Ji Cheng He
Keyword(s):  
Magnetic Field ◽  
Field Gradient ◽  
High Magnetic Field ◽  
Uniform Magnetic Field ◽  
Alloy Composition ◽  
Magnetic Field Gradient ◽  
Obvious Effect ◽  
Ni Alloys ◽  
Field Gradients ◽  
Magnetic Field Gradients

The microstructural changes of the primary Al3Ni phases in hypereutectic Al-Ni alloys solidified under various high magnetic field gradients were investigated. It was found that the application of a magnetic field gradient induced an aligned structure of the primary Al3Ni phases similar to those in a high uniform magnetic field. However, the high magnetic field gradient showed more obvious effect on the alignment of the primary Al3Ni phases than the uniform magnetic field, although this effect strongly depended on the alloy composition.

Distribution of alloying elements and the corresponding structural evolution of Mn–Sb alloys in high magnetic field gradients

2010 ◽  
Vol 25 (9) ◽  
pp. 1718-1727 ◽  
Author(s):  
Tie Liu ◽  
Qiang Wang ◽  
Ao Gao ◽  
Hongwei Zhang ◽  
Kai Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Gradient ◽  
High Magnetic Field ◽  
Magnetic Field Gradient ◽  
Structural Evolution ◽  
Alloying Elements ◽  
Continuous Change ◽  
Solute Element ◽  
Field Gradients ◽  
Magnetic Field Gradients

The distribution of alloying elements and the corresponding structural evolution of Mn–Sb alloys in magnetic field gradients were investigated in detail. It was found that a high magnetic field gradient could control the distribution of solute element in the alloys during the solidification process and therefore resulted in the coexistence of both primary MnSb and Sb phases or the aggregation of the primary MnSb with a continuous change in morphology. The positions where these primary phases located depended on the direction of field gradient. The control of the solute element distribution by a high magnetic field gradient was realized through the magnetic buoyancy force that could drive the migration of Mn element in the melt, originating from the difference in the magnetic susceptibility between Mn and Sb. The effectiveness of this control depends on the alloy composition, specimen dimension, cooling rate, and |BdB/dz| value.

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