Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Magnetization and Superconducting Quantum Interference Device detected Electron Paramagnetic Resonance (SQUID-EPR) of the FIN Trityl Radical

Published

Author(s)

Brant Cage, James H. McNeely, Howard J. Halpern, Stephen E. Russek

Abstract

The Finland trityl paramagnet is characterized by magnetic susceptibility and a new form of quantitative electron paramagnetic resonance (EPR) that utilizes a superconducting quantum interference device (SQUID) 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 >80% electronic polarization at a normalized field of gυBυ0H/kTapproximately equal}3. These results provide information required for theoretical modeling and engineering of the trityl radical for a wide range of applications.
Citation
Journal of Applied Physics
Volume
105
Issue
043905

Keywords

DNP, SQUID-EPR, Trityl

Citation

Cage, B. , McNeely, J. , Halpern, H. and Russek, S. (2009), Magnetization and Superconducting Quantum Interference Device detected Electron Paramagnetic Resonance (SQUID-EPR) of the FIN Trityl Radical, Journal of Applied Physics (Accessed June 24, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created January 23, 2009, Updated October 12, 2021