Digital Film Tools DFT 1.2.1 (x64)

in bulk materials, the ferroelectric nature of bifeo3 has been demonstrated for more than twenty years, as in its rhombohedral phase, the ferroelectric polarization is along the c axis of the perovskite structure [ 74, 75 ]. in addition, the in-plane polar vector of the ferroelectric ordering is always perpendicular to the b axis of the pbnm structure [ 76 ]. by using the ferroelectric nanodomains as a mask, a single epitaxial growth was performed on the (001) surface of a pbnm-type substrate [ 77 ]. the surface of the film was reconstructed and the ferroelectric domains are isolated by the substrate and growth conditions. owing to this, the ferroelectric domains are not connected. they were identified by their piezoresponse contrast using piezoresponse force microscopy and scanning electro-leit microscopy. figure 4 (a) shows the ferroelectric domains of the thin film (yellow) and the substrate (blue). the piezoresponse contrast in the middle part of the domains is zero, which means that the electrical polarization is zero (pz =0), owing to the inversion symmetry of the structure. pfm and scanning electro-leit microscopy images in different directions confirm the inversion symmetry and the zero piezoresponse contrast. as the ferroelectric polarization is always normal to the surface of the film, the surface charge density is 0.5 c m2, while the polarization is +1.9c m2. there is a coercive field of about 1.5 kv cm1 for the ferroelectric domains. the remnant ferroelectric polarization is +0.7 c m2. using xmcd-peem, the authors showed that the ferroelectric switching of the bifeo3 induces a polarization switching of the cofe thin film (magnetization of the ferromagnet is always reversed by 90) ( figure 4 (b) and (c)).

Digital Film Tools DFT 1.2.1 (x64)