Writer with laterally graded spin layer MsT

A spin torque magnetization reversal assisted magnetic recording (STRAMR) writer, comprising:

• (a) a main pole (MP) comprised of a trailing side having a track width w at an air bearing surface (ABS);
• (b) a write gap (WG) formed on the MP trailing side;
• (c) a first trailing shield (TS) on the WG and having a first side facing the MP;
• and
• (d) a spin torque oscillator (STO) formed in the WG between the MP trailing side and first side of the first TS, and comprising a flux guiding layer (FGL) with a magnetization aligned substantially parallel to a WG field (HWG) in the absence of an applied current across the STO, and wherein the STRAMR writer is configured so that the FGL magnetization flips to a direction substantially opposing HWG when a current IB of sufficient magnitude is applied from the first TS across the STO to the MP, the FGL comprises:
• (1) a center portion having a first saturation magnetization×thickness product (MsT1) and a first cross-track width w1 between two sides thereof;
• and
• (2) an outer portion adjoining each side of the FGL center portion and having a second cross-track width w2, and a second saturation magnetization×thickness product (MsT2) where MsT2<MsT1.