Method for making a current-perpendicular-to-the-plane (cpp) magnetoresistive sensor having a low-coercivity reference layer

A method for making a current-perpendicular-to-the-plane (CPP) magnetoresistive sensor having a simple-pinned ferromagnetic reference layer comprising:

• providing a substrate in a vacuum chamber;
• depositing on the substrate at room temperature a seed layer;
• depositing on the seed layer at room temperature a IrMn alloy layer;
• performing a first annealing by subjecting the deposited layers to a temperature between 200-600° C. for between 1-120 minutes;
• cooling the deposited layers to a temperature below 100° C.;
• depositing a ferromagnetic reference layer on the IrMn alloy layer;
• depositing a nonmagnetic spacer layer on the ferromagnetic reference layer;
• depositing a free ferromagnetic layer on the nonmagnetic spacer layer;
• depositing a capping layer on the free layer;
• removing the substrate with deposited layers from the vacuum chamber;
• and
• in the presence of a magnetic field, performing a second annealing by subjecting the deposited layers to a temperature between 200-400° C. for between 0.5-50 hours to thereby increase the exchange coupling between the IrMn alloy layer and the ferromagnetic reference layer.