The influence of the deposition pressure PO 2 and substrate temperature T S during the growth of Bi 2 FeCrO 6 thin films grown by pulsed laser deposition has been investigated. It is found that the high volatility of Bi makes the deposition very difficult and that the growth of pure Bi2FeCrO6 thin films on SrTiO 3 substrates is possible only in a narrow deposition parameter window. We find that the pure Bi 2 FeCrO 6 phase is formed within a narrow window around an oxygen pressure PO 2 =1.2×10 −2 mbar and around a substrate temperature T S =680 °C. At lower temperature or higher pressure, Bi 7.38 Cr 0.62 O 12+x _also called (b*Bi 2 O 3 )and Bi 2 Fe4O 9 /Bi 2 (Fe,Cr) 4 O 9+x phases are detected, while at lower pressure or higher temperature a (Fe,Cr) 3 O 4 phase forms. Some of these secondary phases are not well known and have not been previously studied. We previously reported Fe/Cr cation ordering as the probable origin of the tenfold improvement in magnetization at saturation of our Bi 2 FeCrO 6 film, compared to BiFeO 3 . Here, we address the effect of the degree of cationic ordering on the magnetic properties of the Bi 2 FeCrO 6 single phase. Polarization measurements at room temperature reveal that our Bi2FeCrO6 films have excellent ferroelectric properties with ferroelectric hysteresis loops exhibiting a remanent polarization as high as 55-60 µC/cm 2 along the pseudocubic (001) direction.

Multiferroic properties of γ-Fe 2 O 3-BiFeO 3 /Bi 3.25 La 0.75 Ti 3 O 12 epitaxial composite bi-layers grown on SrRuO 3 /SrTiO 3 (1 1 1) are compared with the properties of single phase BiFeO 3 and Bi 3.25 La 0.75 Ti 3 O 12 thin films. The composite bi-layers show well-saturated hysteresis loops with a low coercive field, a high fatigue resistance and high saturation magnetization. The insulating Bi 3.25 La 0.75 Ti 3 O 12 underlayer reduces significantly both the leakage current and the coercive field of the heterostructure (200 kV cm −1) at the expense of a lower polarization (20 µC cm −2), while the epitaxial γ-Fe 2 O 3 secondary phase that develops within the relaxed epitaxial BiFeO 3 matrix allowed for a high saturation magnetization.

No abstract

Effects of W doping and annealing parameters on the ferroelectricity and fatigue properties of sputtered Bi 3.25 La 0.75 Ti 3 O 12 films J. Vac. Sci. Technol. A 21, 787 (2003); 10.1116/1.1570840 Ferroelectric properties of Bi 3.25 La 0.75 Ti 3 O 12 thin films prepared by chemical solution deposition