The aim of this project is to welcome Prof. Salje from Cambridge University, UK, as a 12 months visitor in the recently launched group of Prof. Kreisel at the CRP Gabriel Lippmann. This project and the visit of Prof. Salje stand within the context of ferroic properties as encountered in ferromagnetic, ferroelectric, ferroelastic, or ferrotoroidic materials. Since recently, a large international research effort is devoted to multiferroic materials which possess simultaneously several ferroic orders and are thus considered multifunctional materials per excellence. An intrinsic property of ferroic materials is the presence of domains (e.g. up and down domains), which implies the presence of domain boundaries, also called domain walls. The atomic structure and physical properties of such domain walls are at the heart of this project.The shared research activity of Profs. Kreisel and Salje is motivated by the new paradigm of ferroic devices where the domain walls, rather than the domains, are the functional element. This field has been coined “domain boundary engineering” or “domain wall nanoelectronics”. It has been argued that the exploitation of the domain walls with a size on the order of 1 nm as well as their different functional properties present a high potential for industrial innovation. Such functionalities include, among others, domain wall conductivity which can be metallic or even superconducting while the surrounding bulk and domains are insulating or semiconducting. The overall aim of the proposed project is to elucidate the atomic and electronic structure of ferroic domain walls. Reminding that the domain walls occur at the nanometer scale, a particular challenge of the project will be to access such details experimentally.Prof. Salje is one of the world leading experts in the field of “domain boundary engineering” which is today regarded as one of the emerging topics in the field of transition metal oxides. It is Prof. Salje who has coined the field “domain boundary engineering” and it is fair to say that his initial work on superconducting domain boundaries in WO3 has initiated this field. The recently launched Luxembourgish research group of Jens Kreisel at the CRP Lippmann has just started an important research program on Domain Boundaries and the group would greatly benefit from Salje’s expertise in this set-up period. Salje and Kreisel consider the visit and collaboration as a win-win situation to exchange mutual techniques and, which in turn motivates a 12 months stay (twice 6 months) to set-up a sustainable research project and collaboration.