Abstract
We report first experimental observation of quantum tunnelling of antiferromagnetic domain walls. The slow dynamics of domain walls in an antiferromagnetic TbFeO3 single crystal has been studied. The magnetization shows exponential time relaxation due to the motion of the domain walls through the energy barrier of a single height U. Above 2.3 K, the rate of relaxation is pure exponential, exp [-U/T]. Below 2.3 K it becomes independent of temperature.