Intensive research is being conducted for the search of multiferroic materials with high magneto-electric (ME) coupling at room temperature. Magneto-electric multiferroics is an attractive class of materials, not only for the diversity of exciting fundamental phenomena that they present but as well the potential technological applications that they foresee, such as energy efficient memory devices and multiple state memories. However multiferroic materials with high ME coupling at room temperature are rare and high quality artificially layered ones are in general difficult to produce. In this respect naturally layered perovskites, such as the Ruddlesden-Popper phases or A/B-site ordered Double perovskites, offer a fascinating route to design and achieve nonexpensive room temperature multiferroics. In these structurally layered materials, distortions of the lattice, such as BO6 octahedron rotations modes, couple to polar dislocation modes, inducing cation ordering and spontaneous ferroelectric polarization, in a mechanism known as the hybrid improper ferroelectricity. The novel idea behind these naturally layered perovskites is that the ferromagnetic and ferroelectric order can be coupled by the same lattice instabilities, providing an indirect but very strong magneto-electric coupling.
By using a set of complementary techniques including local probe studies, one aims to attain a comprehensive study on the competition/cooperation between spin, charge and orbital degrees of freedom at the atomic scale, as well as their complex linkage to the lattice instabilities and functional coupling effects, helping thus to establish new strategies to manufacture novel functional materials.