Intrinsic and quantitative effects of in-plane strain on ferroelectric properties of Mn-doped BiFeO_3 epitaxial films by in situ inducing strain in substrates

摘要

We report in situ manipulation of the in-plane strain ε_(xx)(BFMO) and coercive field E_C(BFMO) of BiFe_(0.95)Mn_(0.05)O_3 (BFMO) films epitaxially grown on La_(0.7)Sr_(0.3)MnO_3 film buffered 0.71Pb(Mg_(1/3)Nb_(2/3))O_3-0.29PbTiO_3 (PMN-PT) substrates. PMN-PT poling-induced strain is effectively transferred to BiFe_(0.95)Mn_(0.05)O_3 films and enhances ε_(xx)(BFMO) and E_C(BFMO), with a gauge factor (ΔE_C(BFMO)/E_C(BFMO))/(δε_(xx)) ～-25 and -326 for the BFMO(001) and BFMO(111) films, respectively. Based on the strain dependence of E_C(BFMO), we established a quantitative relationship between E_C(BFMO) and ε_(xx)(BFMO)- Using ferroelastic strain of PMN-PT, we achieved reversible and non-volatile modulation of strain and E_C(BFMO) of BFMO films, providing an approach for non-volatile and reversible turning of strain and physical properties of ferroelectric films.