Pinning in nomagnetic borocarbides

The field dependences of the Labush parameter in nonmagnetic borocarbides are measured by a method that does not require achieving a critical state. The expected values of the critical current are estimated. The values obtained are two orders of magnitude greater than the results of “direct” measurements performed on the basis of transport (magnetic) experiments. A giant peak effect, which the collective pinning model describes quantitatively well, is observed in the field dependences of the Labush parameter in Y-containing borocarbides.