  Striation of HTS coated conductors (CCs) as a way to reduce their
magnetization AC losses has been the subject of intense research in the past
years by several groups. While the principle of this approach is well
understood, its practical application on commercial material to be used in
power application is still far to be implemented due to manufacturing and
technological constraints. Recent advances in tape quality and striation
technology are now enabling systematic investigations of the influence of the
number of filaments on AC loss reduction with a consistency that was not
available in the past. In this work we demonstrate the technological
feasibility of reducing the magnetization losses of commercially available CC
by striating them into a high number of filaments (up to 120). The loss
reduction exceeds one order of magnitude and does not come at the expense of
current-carrying capability: samples with 10 and 20 filaments are unaffected by
the striation process, while samples with 80 and 120 filaments still retain 80
and 70% of the current-carrying potential, respectively. We also investigate
the transverse resistivity in order to understand the paths followed by the
coupling currents: we found that the coupling current prevalently flows in the
metallic substrate, rather than in and out of the filaments. Finally, we use
oxidation as a method to reduce the coupling currents and losses. The
contribution of this work is three-fold: 1) It describes the know-how to
produce a large number of high quality striations in commercially available
CCs, greatly reducing their losses without extensively degrading their
transport properties; 2) It provides a comprehensive characterization of said
samples (e.g. measurements in a wide frequency range, transverse resistance
profiles, influence of oxidation on DC and AC behavior); 3) It provides new
insight on the patterns of the coupling currents.
