Local Writing of Exchange Biased Domains in a Heterostructure of Co/Pd Pinned by Magnetoelectric Chromia

The writing of micrometer‐scaled exchange bias domains by local, laser heating of a thin‐film heterostructure consisting of a perpendicular anisotropic ferromagnetic Co/Pd multilayer and a (0001) oriented film of the magnetoelectric antiferromagnet Cr 2 O 3 (chromia) is reported. Exchange coupling between chromia's boundary magnetization and the ferromagnet leads to perpendicular exchange bias. Focused scanning magneto‐optical Kerr measurements are used to measure local hysteresis loops and create a map of the exchange bias distribution as a function of the local boundary magnetization imprinted in the antiferromagnetic pinning layer on field cooling. The robust boundary magnetization of the Cr 2 O 3 fundamentally alters the exchange bias mechanism, enabling the writing of micrometer‐scaled regions of oppositely directed exchange bias using a focused laser beam.