Quantum Spin Wave Excited from a Cr-Dy Single-Molecule Magnet

Here we report the first observed coexistence of quantum spin wave excitation and single-molecule magnet behavior in a fluoride-bridged mixed chromium(III) and dysprosium(III) complex, namely Dy4Cr2(μ3-F)2(mdea)3(piv)10, which shows a large ferrimagnetic ground moment with restricted quantum tunneling gap (< 3.8 × 10−7 cm−1) up to nine levels, leading to an uniaxial magnetic anisotropic energy barrier of 12 cm−1 and opened hysteresis loop at 0.4 K. More importantly, spin wave excitation has been observed by using inelastic neutron scattering spectroscopy, and the data can be well explained by the L&E-band theory with Δ/2 = 2.08 cm−1 and ε(q) = 2.5 cm−1, providing unambiguous evidence for spin wave excitations.