A PMR writer is disclosed wherein magnetic flux return from a magnetic medium to a main pole is substantially greater through a trailing shield structure than through a leading return loop comprised of a leading shield, return path layer (RTP), and back gap connection (BGC). Magnetic impedance is increased between the RTP and main pole in the leading return loop by removing one or more layers in the BGC and replacing with dielectric material and non-magnetic metal to form a dielectric gap between the RTP and main pole. The non-magnetic metal may be Cu that is electrically isolated from coils within the write head. As a result, area density control and bit error rate are improved over a conventional dual write shield (DWS) structure comprising two flux return pathways. Moreover, adjacent track erasure is maintained at a level similar to a DWS design.