Impurity Nuclear-Magnetic-Resonance Shifts and Spin-Lattice Relaxation Rates in Al: V, Al: Cr, and Al: Mn

1969 ◽  
Vol 23 (5) ◽  
pp. 233-236 ◽  
Author(s):  
Albert Narath ◽  
H. T. Weaver
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Nuclear Magnetic

Nuclear magnetic resonance of 169 Tm (enhanced) and 31 P in TmPO 4

1983 ◽  
Vol 387 (1792) ◽  
pp. 75-90 ◽  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Energy Levels ◽  
Lattice Relaxation ◽  
Simple Calculation ◽  
Spin Lattice Relaxation ◽  
Field Calculation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Nuclear Magnetic

The enhanced nuclear magnetic resonance (n. m. r.) spectrum of 169 Tm ( I = ½) in the tetragonal compound TmPO 4 has been measured from 1.6 K to 30 K. It is highly anisotropic, with γ /2π = 11.34 and 276MHzT -1 , parallel and perpendicular to the c -axis respectively, at the lowest temperatures. The corresponding values of the Van Vleck electronic susceptibility per ion are 0.0231 and 0.805 μ B T -1 . Above 4 K the values of γ /2π become temperature dependent as excited levels become populated, and the results are discussed in the light of a crystal field calculation of the energy levels and wave functions. The n. m. r. spectrum of 31 P ( I = ½) is shown to exhibit an anisotropic paramagnetic shift, mainly dipolar in origin, exactly proportional to the electronic susceptibility of the Tm 3+ ions, and this is used to extrapolate the measurement of γ for 169 Tm up to 64 K in the perpendicular direction. A simple calculation of the direct process for spin-lattice relaxation shows that this is orders of magnitude too slow to account for the observed relaxation rates, which must be ascribed to the presence of paramagnetic impurities.

scholarly journals Advances in the Interpretation of Frequency-Dependent Nuclear Magnetic Resonance Measurements from Porous Material

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3688 ◽  
Author(s):  
David Faux ◽  
Rémi Kogon ◽  
Villiam Bortolotti ◽  
Peter McDonald
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relative Motion ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Historic Data ◽  
Field Cycling ◽  
Nuclear Magnetic

Fast-field-cycling nuclear magnetic resonance (FFC-NMR) is a powerful technique for non-destructively probing the properties of fluids contained within the pores of porous materials. FFC-NMR measures the spin–lattice relaxation rate R 1 ( f ) as a function of NMR frequency f over the kHz to MHz range. The shape and magnitude of the R 1 ( f ) dispersion curve is exquisitely sensitive to the relative motion of pairs of spins over time scales of picoseconds to microseconds. To extract information on the nano-scale dynamics of spins, it is necessary to identify a model that describes the relative motion of pairs of spins, to translate the model dynamics to a prediction of R 1 ( f ) and then to fit to the experimental dispersion. The principles underpinning one such model, the 3 τ model, are described here. We present a new fitting package using the 3 τ model, called 3TM, that allows users to achieve excellent fits to experimental relaxation rates over the full frequency range to yield five material properties and much additional derived information. 3TM is demonstrated on historic data for mortar and plaster paste samples.

Nuclear Magnetic Resonance Brain Imaging in Chronic Schizophrenia

1987 ◽  
Vol 150 (2) ◽  
pp. 161-163 ◽  
Author(s):  
J. A. O. Besson ◽  
F. M. Corrigan ◽  
G. R. Cherryman ◽  
F. W. Smith
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Lattice Relaxation ◽  
Chronic Schizophrenia ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Magnetic Resonance Brain Imaging ◽  
Normal Controls ◽  
Nuclear Magnetic

Patients with chronic schizophrenia were examined by nuclear magnetic resonance imaging of the brain. Subgroups of the syndrome with high positive or high negative symptom scores and ventricular dilatation were compared with each other and with normal controls in respect of regional spin lattice relaxation time (T1) changes. Significant differences were not observed between the schizophrenic subgroups and controls but there were significant differences between the subgroups themselves. The presence of tardive dyskinesia was associated with increased T1 of the basal ganglia. The significance of these results is discussed in relation to findings using other techniques.

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