Development of Room Temperature Multiferroic SmFeO3 Thin Films

Multiferroic materials are very popular in recent decades due to its versatile functionalities for applications. A result development of new materials that possesses multiferroicity is of great importance. SmFeO₃ (SFO) has been considered as new room temperature single-phase multiferroic material for few years. SFO exhibits anti-ferromagnetism and significant magnetization below T_N ∼ 670 K. However, the existence of ferroelectricity of single crystal SFO is still under debate.
In this work, we focus on the growth of epitaxial SFO thin films on different single crystalline substrates (LaAlO₃ and NdGaO₃ ) in order to trigger the presence of room temperature ferroelectricity. Atomic force microscopy has been used to check the surface morphology to prove the layer-by-layer epitaxy growth. To certify the interfacial strain between two different oxide materials, high resolution XRD is adopted. The ferroelectricity of SFO grown on NdGaO₃ substrate has been identified by the piezoresponse force microscopy (PFM). Multiple techniques have been exploited to verify the ferroelectricity in the strained SFO thin films. The existence of the ferroelectricity is further supported via density function theory. Out results identify a new room temperature single-phase multiferroic system.