Evaporable lanthanide single-ion magnet

Abstract

Two thermally stable single-ion magnets containing a dysprosium ion with the ligand fod (1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octadione) and bpy (2,2′-bipyridine) or phen (1,10-phenathroline) were synthesized, named 1Dy (Dyfod₃bpy) and 2Dy (Dyfod₃phen). They both have 6 oxygen atoms and 2 nitrogen atoms around the lanthanide metal ion in the center, forming a pseudo-D_4d coordination structure. Dynamic magnetic studies show that they both exhibit temperature dependent processes and quantum tunneling relaxation under zero applied dc field. Interestingly, 1Dy melts at 90 °C and evaporates at 269 °C to form the amorphous compound 3Dy. The XRD data show that there is little change of the local structure between 1Dy and the evaporated sample 3Dy. Magnetic measurements show that 3Dy retains the SMM properties, but the relaxation barrier shifts from 87 K to 122 K and the quantum tunneling becomes slower.