MUON-SPIN-RELAXATION STUDY OF THE GROUND-STATE OF THE 2-DIMENSIONAL S=1 KAGOME ANTIFERROMAGNET ETHYL-4,5-DIHYDRO-1H-IMIDAZOL-L-OXYL-3-N-OXIDE]BF4

Zero- and longitudinal-field positive muon spin relaxation (mu(+) SR) measurements were carried out from 300 K to 30 mK to study a ground st ate of m-MPYNN . BF4 which is known to be a two-dimensional kagome ant iferromagnet with S=1 by ac-susceptibility measurements. An implanted muon is expected to make a hydrogen bonding state with F- ions in the crystal. Muon-spin depolarization by a dynamically fluctuating compone nt of an internal field was still observed at 30 mK. This fluctuating component is suggested to be caused by an intradimer ferromagnetic int eraction of 2J(0)/k(B) = 23.3 K between radicals. No clear long-range magnetic ordering of the dimer spins was observed down to 30 mK, sugge sting that the ground state of m-MPYNN . BF4 was nonmagnetic.