Room-temperature multiferroicity in GaFeO$_3$ thin film grown on (100)Si substrate

Room-temperature magnetoelectric multiferroicity has been observed in c-axis oriented GaFeO$_3$ thin films (space group $Pna2_1$), grown on economic and technologically important (100)Si substrates by pulsed laser deposition technique. Structural analysis and comprehensive mapping of Ga:Fe ratio across a length scale range of 10$^4$ reveal coexistence of epitaxial and chemical strain. It induces formation of finer magnetic domains and large magnetoelectric coupling - decrease in remanent polarization by $\sim$21\% under $\sim$50 kOe. Magnetic force microscopy reveals presence of both finer ($<$100 nm) and coarser ($\sim$2 $\mu$m) magnetic domains. Strong multiferroicity in epitaxial GaFeO$_3$ thin films, grown on (100)Si substrate, brighten the prospect of their integration with Si-based electronics and could pave the way for development of economic and more efficient electromechanical, electrooptic or magnetoelectric sensor devices.