Magnetoelectric fatigue of Ho-doped Bi5Ti3FeO15 films under the action of bipolar electrical cycling

Abstract

Pure and Ho-doped Bi₅Ti₃FeO₁₅ magnetoelectric films were prepared by a sol–gel method, and the influence of bipolar electrical cycling on the ferroelectric, leakage and magnetoelectric properties of the films were studied in detail. It was demonstrated that the ferroelectric, leakage, and especially the magnetoelectric performance are depressed significantly after 10⁹ bipolar electric cycles for the pure Bi₅Ti₃FeO₁₅ films. The ferroelectric and leakage fatigue behaviors are attributed to the defect dipoles and other agglomerated space charges on the surface after bipolar electrical cycling, which further results in magnetoelectric fatigue. In comparison, Ho-doped Bi₅Ti₃FeO₁₅ films show much stronger fatigue resistance than Bi₅Ti₃FeO₁₅ films. The ferroelectric polarization and magnetoelectric coefficient only slightly decreased after doping with Ho. The good magnetoelectric fatigue resistance mainly derives from the depression of ferroelectric and leakage fatigue. The present work provides a possible way to improve the anti-fatigue behaviors of magnetoelectric films for application in functional devices.