Magnetic memory in ferromagnetic thin films via exchange coupling

We show the possibility of creating magnetic domain memory in thin ferromagnetic films by inducing spatially varying exchange coupling interactions. We evidence this phenomenon in a perpendicular exchange bias film made of [Co/Pd] IrMn multilayers. Our coherent x-ray magnetic scattering speckle correlation study shows that the film exhibits no memory at room temperature but acquires a very high degree of magnetic memory, above 80% with subsequent field cycling when the sample is zero-field cooled below the blocking temperature of the IrMn layers (T<275 K).