Multiferroic materials with strong magnetoelectric (ME) coupling, in which magnetism (or electric polarization) can be controlled via an electric (or a magnetic) field, are promising materials due to their possible potential application in data-storage technology.

Most of the reported bulk single multiferroic materials are based on 3d-transition metal oxides, which exhibit low-temperature multiferroic ordering and weak ME coupling.

Systems containing 4d/5d-transition metal oxides should be potential candidates due to their compelling effects of extended d-orbitals and larger spin-orbit coupling to enhance multiferroic ordering and ME coupling. Moreover, in the case of the inverse Dzyaloshinskii-Moriya (DM) interaction and spin-dependent p-d hybridization, the strength of the ME coupling depends on several factors, one of which is the spin-orbit coupling, where a larger spin-orbit coupling gives rise to a larger polarization.

It has been theoretically predicted that 3d-5d double perovskite systems could serve as better multiferroics, where the higher d-orbitals will potentially enhance both the ordering temperature and the ME coupling.

One of the drawbacks is that most of the 4d/5d-orbital-based systems are electrically leaky (less insulating). This is counterproductive for multiferroic samples, as this hinders both dielectric and ME investigation and is further detrimental to practical applications. Therefore, experimental realizations of bulk magnetoelectric multiferroic materials containing magnetic (non-d⁰) 4d/5d-orbitals are rare due to the scarcity of good insulating materials.

We design new ME materials containing 4d-4f orbitals and investigate via bulk (magnetic, dielectric, ferroelectric) and spectroscopic (X-ray and Neutron scattering) investigations, which will find a route towards enhancement of multiferroic ordering temperature and ME coupling strength in a single material to enable potential application in a long-run.