Low coercivity giant magnetoresistance with perpendicular magnetic anisotropy

• We find an extremely small coercivity giant magnetoresistance (GMR) structure for the out-of-plane magnetic field.
• The key ingredient of small coercivity is a TiO2 seed layer.
• Such a small coercivity GMR structure will be useful for automotive applications such as wheel speed, rotation, and position sensors.

We find the perpendicular magnetic anisotropy giant magnetoresistance structure, whose coercivity is less than 10 Oe. We reveal that the coercivity of free layer can be smaller than 5 Oe in Co/Pd/Cu/[Co/Pd]4 multilayer structure with a TiO2 seed layer. The TiO2 seed layer plays a critical role in the small coercivity of free layer. The GMR ratio is around 1–1.8% for the out-of-plane magnetic fields, and the maximum MR sensitivity of 0.12%/Oe is achieved.