ZF /μSR of an organic weak ferromagnet with Tc=35 /K

Zero-field μSR has been used to study the internal field in the β crystal phase of the dithia-diazolyl molecular radical p- NC( C₆F₄) ( CNSSN) , which is a canted antiferromagnet showing spontaneous magnetisation below 35 K. Two distinct frequencies are resolved in the zero-field muon spin rotation signal, which have been assigned to muon states bonded at two different sites on the CNSSN ring. The muon data shows that the easy direction for the spin structure is along the b-axis. Muon spin relaxation below the transition follows the power law expected for two magnon scattering along with some sharper features near the transition suggesting strong magnon-phonon interaction.