The range of applied magnetic fieldHcorresponding to the stability of mixed state with a fixed magnetic inductionBis determined for a high-TcsuperconductingYBa2Cu3Oxsingle crystal forH⊥c-axis. For this purpose, the field dependences of the contribution&mgr;vto the dynamic magnetic permeability&mgr;ac′are analyzed for the hysteresis loops&mgr;v(H)in the temperature range from 70 to 84 K. It is shown that the&mgr;v(H)hysteresis can be interpreted in terms of the interaction between the vortex lattice and the surface and is associated with theB(H)hysteresis as a manifestation of the Bean–Livingston surface barrier. As a result, the&mgr;v(H)hysteresis loops corresponding to different temperatures can be described by a universal curve in dimensionless coordinates. The obtained estimates and the available experimental data reveal a significant suppression of the surface barrier in actual YBaCuO single crystals as compared to the barrier predicted for a perfect surface. The lower branch of the&mgr;v(H)hysteresis loop, which corresponds to increasingH,is found to be close to the equilibrium&mgr;v(H)curve, and the surface barrier appreciably affects the behavior of&mgr;v(H)only for decreasing field, i.e., the emergence of magnetic vortices from the sample surface. ©1998 American Institute of Physics.