Apparent RM variations along pulse phase detected for eight pulsars. Panel (a) displays the RM variations after subtracting the average RM value. Panel (b) PA curves. Panel (c) polarization pulse profiles, where solid black, dashed red, and dotted blue curves denote the total intensity, linear intensity, and circular polarization intensity, respectively. The profiles were normalized by the maximal intensity and the phase of the intensity peak was set at 0.5.