the potential discovery of new physics associated with the MF coupling. Domains and domain walls Like any ferroic material, a multiferroic system is fragmented into domains. A domain is a spatially extended region with a constant direction and phase of its order parameters. Neighbouring domains are separated by transition regions called domain walls. Properties of multiferroic domains In contrast to materials with a single ferroic order, domains in multiferroics have additional properties and functionalities. For instance, they are characterized by an assembly of at least two order parameters. The order parameters may be independent (typical yet not mandatory for a Type-I multiferroic) or coupled (mandatory for a Type-II multiferroic). Many outstanding properties that distinguish domains in multiferroics from those in materials with a single ferroic order are consequences of the coupling between the order parameters. The coupling can lead to patterns with a distribution and/or topology of domains that is exclusive to multiferroics. The order-parameter coupling is usually homogeneous across a domain, i.e., gradient effects are negligible. In some cases the averaged net value of the order parameter for a domain pattern is more relevant for the coupling than the value of the order parameter of an individual domain. These issues lead to novel functionalities which explain the current interest in these materials. Properties of multiferroic domain walls Domain walls are spatially extended regions of transition mediating the transfer of the order parameter from one domain to another. In comparison to the domains the domain walls are not homogeneous and they can have a lower symmetry. This may modify the properties of a multiferroic and the coupling of its order parameters. Multiferroic domain walls may display particular static and dynamic properties. Static properties refer to stationary walls. They can result from The reduced dimensionality The finite width of the wall The different symmetry of the wall The inherent chemical, electronic, or order-parameter inhomogeneity within the walls and the resulting gradient effects. Synthesis Multiferroic properties can appear in a large variety of materials. Therefore, several conventional material fabrication routes are used, including solid state synthesis, hydrothermal synthesis, sol-gel processing, vacuum based deposition, and floating zone. Some types of multiferroics require more specialized processing techniques, such as Vacuum based deposition (for instance: MBE, PLD) for thin film deposition to exploit certain advantages that may come with 2-dimensional layered structures such as: strain mediated multiferroics, heterostructures, anisotropy. High pressure solid state synthesis to