Single-molecule magnet [Tb(hfac)₃(2pyNO)] (2pyNO = t-butyl 2-pyridyl nitroxide) with a relatively high barrier of magnetization reversal

The crystallographic analysis of the title compound shows that there are two crystallographically independent molecules in a unit cell. The magnetic study clarified that every molecule behaved as a single-molecule magnet. Two series of the out-of-phase ac susceptibility signals appeared around 10 K even at zero dc field. The activation energies (Δ) for the magnetization reversal were estimated as Δ⁽¹⁾/k_B = 39.2(3) K with τ₀⁽¹⁾ = 4.2(4) × 10^-8 s and Δ⁽²⁾/k_B = 36(2) K with τ₀ ⁽²⁾ = 4.1(12) × 10^-7 s, where τ₀ stands for the pre-exponential factor in the Arrhenius analysis. Magnetic hysteresis was recorded at 1.6 K by means of a pulsed-field technique. The role of exchange coupling is discussed.