  We study the statistical features of magnetic noise accompanying the dynamic
fracture of steel samples during mixed type fracture, where the overall ductile
character of crack propagation is interrupted by a sudden brittle jump. The
structure of the voltage time series is investigated by identifying discrete
peaks which correspond to elementary steps of the jerky cracking process. We
show that the height, duration, area, and energy of peaks have power law
distributions with exponents falling close to the corresponding values of pure
ductile fracture. For single peaks a power law correlation of the height and
area with the width is evidenced, however, the mixed nature of fracture gives
rise to a crossover between two regimes of different exponents. The average
pulse shape of micro-cracking events has a parabolic form with a right handed
asymmetry similarly to quasi-static fracture propagation. The asymmetry emerges
due to stress localization at the advancing crack front.
