Electron spin resonance and its implication on the maximum nuclear polarization of deuterated solid target materials

Heckmann, J.; Meyer, W.; Radtke, Edgar; Reicherz, G.; Goertz, S.

doi:10.1103/physrevb.74.134418

Cited by 56 publications

(109 citation statements)

References 14 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…The exact nature of the broadening is not clear; however, temperature dependent broadening can be a function of internal demagnetization fields, or short range order approaching a phase transition. 16,22,27 These results are in contrast to recent EPR work on diluted trityl systems which exhibited little to no linewidth dependence on temperature down to 1 K. 25,26 This indicates that at low temperatures, the EPR linewidth is highly dependent on the trityl concentration, whereas at temperatures above about 10 K, there is little dependence. It would be of interest to examine the linewidth as a function of concentration, as well the orientationdependent single crystal linewidth.…”

Section: Resultscontrasting

confidence: 55%

“…Recent works have indicated that line broadening reduces DNP efficiency. 25,26 Therefore this result provides a mechanism for the decrease in DNP at high trityl concentrations.…”

Section: Discussionmentioning

confidence: 98%

“…24 at 100 K, and 3.16 ϫ 10 −4 in Ref. 25 for a dilute solution ͑15 mM͒ in propanediol at 1 K and 70 GHz. This agreement is reasonable given the different conditions such as temperature and radical concentration.…”

Section: Resultsmentioning

confidence: 99%

“…We attribute the asymmetry to g-tensor anisotropy, as has been observed in other works using dilute solid solutions. [24][25][26] The inset line is a smoothed first derivative and, in accordance with standard EPR practice, we assign the zero crossing to g Ќ and the maximum to g ʈ . Smoothing is required before taking the first derivative due to noise.…”

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Thermomagnetic properties of the Finland trityl radical

Cage

McNeely

Russek

et al. 2009

Journal of Applied Physics

View full text Add to dashboard Cite

The Finland trityl paramagnet is characterized by magnetic susceptibility and a new form of quantitative electron paramagnetic resonance ͑EPR͒ that utilizes a superconducting quantum interference device ͑SQUID͒ as a detection method. This radical is of interest due to its use as a dynamic nuclear polarization agent as well as a potential magnetic refrigerant and quantum computing bit. The SQUID-EPR data show that the EPR linewidth of a concentrated trityl powder decreases dramatically from 4.4 to 1.4 mT as the temperature is increased from 1.8 to 10 K. The quantitative nature of SQUID-EPR is used to thermodynamically quantify the EPR energy transfer times and saturated fractions. At 95 GHz and 1.8 K, only 40% of the spins are in resonance at the onset of saturation. Conventional dc magnetic susceptibility over 1.8-150 K indicates an S =1/ 2 Curie-Weiss relationship with little long range interaction. Magnetization versus applied field at 1.8 and 4 K fits a Brillouin function with Ͼ80% electronic polarization at a normalized field of g B 0 H / kT Ϸ 3. These results provide information required for theoretical modeling and engineering of the trityl radical for a wide range of applications.

show abstract

Section: Resultscontrasting

confidence: 55%

“…Recent works have indicated that line broadening reduces DNP efficiency. 25,26 Therefore this result provides a mechanism for the decrease in DNP at high trityl concentrations.…”

Section: Discussionmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Thermomagnetic properties of the Finland trityl radical

Cage

McNeely

Russek

et al. 2009

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…16,17 Other radicals such as BDPA, 18 DPPH, 19 and galvinoxyl 20 have been used with some success as well as novel methods such as photoinduced radicals 21 and paramagnetic centers within nanoparticles. 22,23 Nitroxide free radicals have relatively wide EPR linewidths, which are better suited for DNP of high-γ nuclei such as 1 H spins and also provide decent polarization levels for low-γ nuclei such as 13 C. 24 This class of free radicals maintain their popularity by being comparatively inexpensive, highly water soluble, easily scavenged, and effective for cross polarization DNP. [25][26][27][28][29][30] Additionally, the DNP efficiency of these radicals may be increased through other means such as deuteration of the glassing matrix.…”

Section: Introductionmentioning

confidence: 99%

Influence of Dy3+ and Tb3+ doping on 13C dynamic nuclear polarization

Niedbalski

Parish

Kiswandhi

et al. 2017

The Journal of Chemical Physics

View full text Add to dashboard Cite

Dynamic nuclear polarization (DNP) is a technique that uses a microwave-driven transfer of high spin alignment from electrons to nuclear spins. This is most effective at low temperature and high magnetic field, and with the invention of the dissolution method, the amplified nuclear magnetic resonance (NMR) signals in the frozen state in DNP can be harnessed in the liquid-state at physiologically acceptable temperature for in vitro and in vivo metabolic studies. A current optimization practice in dissolution DNP is to dope the sample with trace amounts of lanthanides such as Gd 3+ or Ho 3+ , which further improves the polarization. While Gd 3+ and Ho 3+ have been optimized for use in dissolution DNP, other lanthanides have not been exhaustively studied for use in 13 C DNP applications. In this work, two additional lanthanides with relatively high magnetic moments, Dy 3+ and Tb 3+ , were extensively optimized and tested as doping additives for 13 C DNP at 3.35 T and 1.2 K. We have found that both of these lanthanides are also beneficial additives, to a varying degree, for 13 C DNP. The optimal concentrations of Dy 3+ (1.5 mM) and Tb 3+ (0.25 mM) for 13 C DNP were found to be less than that of Gd 3+ (2 mM). W-band electron paramagnetic resonance shows that these enhancements due to Dy 3+ and Tb 3+ doping are accompanied by shortening of electron T 1 of trityl OX063 free radical. Furthermore, when dissolution was employed, Tb 3+ -doped samples were found to have similar liquid-state 13 C NMR signal enhancements compared to samples doped with Gd 3+ , and both Tb 3+ and Dy 3+ had a negligible liquid-state nuclear T 1 shortening effect which contrasts with the significant reduction in T 1 when using Gd 3+ . Our results show that Dy 3+ doping and Tb 3+ doping have a beneficial impact on 13 C DNP both in the solid and liquid states, and that Tb 3+ in particular could be used as a potential alternative to Gd 3+ in 13 C dissolution DNP experiments. Published by AIP Publishing.

show abstract