Quantum magnetic deflagration in Mn12 acetate

We report controlled ignition of magnetization reversal avalanches by surface acoustic waves in a single crystal of ${\mathrm{Mn}}_{12}$ acetate. Our data show that the speed of the avalanche exhibits maxima on the magnetic field at the tunneling resonances of ${\mathrm{Mn}}_{12}$. Combined with the evidence of magnetic deflagration in ${\mathrm{Mn}}_{12}$ acetate [Y. Suzuki et al., Phys. Rev. Lett. 95, 147201 (2005)], this suggests a novel physical phenomenon: deflagration assisted by quantum tunneling.