A novel anisotropic saturation magnetization phenomenon in flexible Mn-doped BiFeO3 thin films for wearable device

Abstract

Pure inorganic flexible thin film with anisotropic magnetism is crucial for high temperature flexible/wearable spintronic devices and magnetic sensors. Here, a pure inorganic flexible Mn-doped BiMn0.05Fe0.95O3 (BMFO) thin film with a novel anisotropic saturation magnetization phenomenon is demonstrated on (001)-oriented fluorophlogopite (F-Mica) single-crystalline substrates by sol–gel method. The results of XRD indicate that the intensity ratios of the (101) and (110) direction increases with the increase in thicknesses. And an obvious anisotropy behavior in magnetization was observed in the thicker flexible BMFO thin films, and the anisotropic magnetization is slowly weakened as the thickness decreases. Meanwhile, the saturation magnetization (Ms) of both in-plane and out-of-plane increases with the increase in the thickness. These results indicate that the thickness can modulate the anisotropic magnetism for the flexible BMFO thin films. The maximum value of (Ms-in-plane-Ms-out-of-plane) is obtained in the flexible BMFO sample with the thickness of 550 nm. Moreover, the real nonvolatile ferroelectric polarization with Pr = 58.22 μC/cm2 was obtained in the flexible BMFO sample with the thickness of 336 nm. These flexible BMFO thin films with anisotropic saturation magnetism, mechanical anti-fatigue characters and well ferroelectric properties are promising for the applications in high temperature flexible spintronics and magnetic sensors.