1995A&A...293..153X

We present polarimetric observations of 19 pulsars, at 10.55GHz. For most of them this is the highest frequency they have been observed polarimetrically so far. We confirm that the average profile becomes progressively depolarized at high frequencies where emission is thought to originate from altitudes closer to the stellar polar cap. In most cases studied the observed depolarization is associated with distortions of the polarization angle curve, indicating orthogonally or quasi-orthogonally polarized emission. However, in some rare cases severe depolarization is observed which is not associated with such distortions, implying a different depolarization mechanism. An anti-correlation has been found between the depolarization index and the accelerating potential above the polar cap surface, which probably influences the elementary beaming of curvature radiation. Weak correlations were found between the depolarization index and those parameters that characterize the geometry of the emission region, with the core width correlating most strongly. Two of the pulsars in our sample exhibit mode changes. The intensity mode changes are more remarkable than those at lower frequencies, whereas the associated polarization mode changes are less frequency dependent.