Nanoscale characterization of emergent phenomena in multiferroics

Multiferroics exhibit intriguing physical properties and in turn promise new device applications - as a result of the coupling between their order parameters. In this review article, we introduce photoemission electron microscopy (PEEM) as a powerful tool to study multiferroicity with the capability of probing the charge, spin and orbital states of a material simultaneously with nanoscale spatial resolution and element sensitivity. Several systematical studies of ferroelectricity, antiferromagnetism, and multiferroicity using PEEM are discussed. In the end, we outline several challenges remaining in multiferroic research, and how PEEM can be employed as an important characterization tool providing critical information to understand the emergent phenomena in multiferroics.