Structural Characteristics and Ferroelectric Properties of Bismuth-Based Compound Thin Films Crystallized by Hot Isostatic Pressing

摘要

After depositing amorphous (Bi_0.5La_0.5)(Ni_0.5Ti_0.5)O_3 (BLNT) films on BLNT seed layer/Pt(100)/ MgO(100) substrates by room-temperature sputtering, the crystallization of the perovskite-struc-tured films has been tried by hot isostatic pressing (HIP). The samples with a single-phase perovskite structure HIP-treated at 800°C for 1 h under gas pressures of 0.5-1.0 MPa showed good crystallinity of Δθ=0.96-0.98° without accompanying the precipitation of the secondary phase. It was confirmed that a large root mean square roughness value of 44.2 nm for the sample HIP-treated at 800°C for 1 h under gas pressure of 0.1 MPa is due to innumerable Bi_4Ti_3O_12-like rod-shaped grains precipitated in the film surface, based on atomic force microscopy. It is shown that the BLNT sample HIP-treated at 800°C for 1 h under gas pressure of 1.0 MPa exhibits the best hysteresis loop shape with a remanent polarization of P_r = 5 μC/cm~2 and a coercive field of E_c= 150 kV/cm of the six.