Role of the antiferromagnetic bulk spins in exchange bias

• We address the role of bulk antiferromagnetic spins in the exchange bias phenomenon.
• Significant experiments on how bulk AFM spins determine exchange bias are highlighted.
• We explain the model that accounts for experimental results.

This “Critical Focused Issue” presents a brief review of experiments and models which describe the origin of exchange bias in epitaxial or textured ferromagnetic/antiferromagnetic bilayers. Evidence is presented which clearly indicates that inner, uncompensated, pinned moments in the bulk of the antiferromagnet (AFM) play a very important role in setting the magnitude of the exchange bias. A critical evaluation of the extensive literature in the field indicates that it is useful to think of this bulk, pinned uncompensated moments as a new type of a ferromagnet which has a low total moment, an ordering temperature given by the AFM Néel temperature, with parallel aligned moments randomly distributed on the regular AFM lattice.

Figure optionsDownload as PowerPoint slide