High-dielectric-constant Bi0.92Ho0.08Fe[1-x]MnxO3 ferroelectric film and preparation method thereof

Abstract

The invention relates to a high-dielectric-constant Bi0.92Ho0.08Fe[1-x]MnxO3 ferroelectric film (x=0.01-0.05) and a preparation method thereof. The film is in a distorted perovskite structure belonging to a rhombohedral system, and has favorable uniformity; and the remanent polarization is 88-116 mu C / cm<2>, and the dielectric constant is 223.1-327.3. The preparation method comprises the following steps: dissolving bismuth nitrate, iron nitrate, holmium nitrate and manganese acetate in an ethylene glycol monomethyl ether-acetic anhydride mixed solution to obtain a precursor solution; evenly spin-coating the precursor solution on a substrate, baking to obtain a dry film, and annealing to obtain a Bi0.92Ho0.08Fe[1-x]MnxO3 film; and spin-coating the precursor solution again, baking and annealing to the required film thickness, thereby obtaining the film. The method has the advantages of simple facility request and controllable doping amount, and can greatly enhance the dielectric properties of the BiFeO3 film.

Description

Technical field [0001] The invention belongs to the field of functional materials, and specifically relates to a high dielectric constant Bi 0.92 Ho 0.08 Fe 1-x Mn x O 3 Ferroelectric thin film and its preparation method. Background technique [0002] As a typical single-phase multiferroic perovskite material, BiFeO 3 It is one of the few materials that have both ferroelectricity and ferromagnetism at room temperature (T c =1103K, T N =640K). BiFeO 3 It has magnetoelectric coupling properties at room temperature and has potential application prospects in information storage, spintronic devices and pyroelectric effects, so BiFeO 3 It has become a hot research topic in recent years. [0003] However, the pure phase BiFeO 3 The material has a large leakage current, and the root cause of leakage is BiFeO 3 Unstable and volatile Bi 3+ Ion, with Bi 3+ The volatilization of ions, the sintering process will form oxygen vacancies in the material, and cause Fe 3+ Price reduced to Fe 2+ , Pro...

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Problems solved by technology

Due to the limitations of the preparation process and preparation equipment, and BiFeO 3 The temperature range that exists is very narrow, so it is inevitable that impurity phases will be generated when preparing samples, resulting in BiFeO 3 The material has a large leakage current, low resistivity, small dielectric constant, and low withstand voltage. It is difficult to obtain a saturated hysteresis loop and a large remanent polarization, which seriously hinders the application of the material in magnetic storage, etc. field application

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