Dynamic proton polarization in propanediol below 0.5 K

Abstract

Dynamic proton polarizations of +98−4+2% and −100−0+4% have been obtained in 1,2-propanediol doped with Crv-complexes, at a sample temperature of about 0.37 K in a 2.5 T magnetic field. Short polarization time constants indicate that the mechanism for obtaining these high polarizations is the cooling of the electron spin-spin interaction reservoir. The temperature and field dependence of the proton spin-lattice relaxation time were measured down to 55 mK and 0.2 T.