The present embodiments relate to a tunnel magnetoresistance (TMR) element. The TMR element can include a free layer comprising a metallic alloy that is doped using a dopant element. In some instances, the metallic alloy comprises a cobalt-iron (CoFe) alloy. The present embodiments relate to doping a small amount of an element (e.g., hafnium (Hf), tantalum (Ta), Yttrium (Y)) in a high flux CoFe layer of a tunnel magnetoresistance (TMR) element. The small amount of dopant can suppress a long-range order in the CoFe film. The amorphous state of a CoFe alloy can be induced by the dopant and result in a magnetically soft layer. A resistance of the TMR element can be modified based on an application of an external magnetic field to the free layer and the pin layer.

A method of forming a read head is described where a Tunneling Magnetoresistive (TMR) stack of layers comprised of a free layer (FL) and having sidewalls separated by a cross-track width is formed on a bottom shield. In subsequent steps, a first insulation layer and longitudinal biasing layer are formed on the sidewalls and bottom shield. After a TMR sensor backside is formed that exposes the bottom shield, a second insulation layer and permanent magnet (PM) layer are deposited on exposed portions of the bottom shield. Thereafter, the PM layer magnetization is initialized in a direction that adjusts FL bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior asymmetry measurement.