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Abnormal magnetic property in Fe-doped BaTio3 multiferroics

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The result of magnetization measurements showed that the magnetization at a magnetic field as high as 1 T abnormally depends on x, increases with increasing x to a maximum at x=0.1 then decreases monotonously afterward. There are possibilities to account for this anomalous magnetic behavior such as the Fe3+-to-Fe4+ and/or Ti4+-to-Ti3+ change(s) induced by oxygen vacancies. The substitution of Fe into Ti sites also changes the conductivity of the material and impurity (acceptor) levels in the band gap. | Nguyễn Văn Đăng và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 96(08): 49 - 54 ABNORMAL MAGNETIC PROPERTY IN Fe-DOPED BaTiO3 MULTIFERROICS Nguyen Van Dang1*, Nguyen Thi Dung1, Nguyen Van Khien1, To Manh Kien2, Nguyen Khac Hung1 1 College of Science - TNU, 2Xuan Mai High School – Hanoi City SUMMARY Samples of multiferroic BaTi1-xFexO3 material (x = 0.0, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.2 and 0.3) were synthesized by using the solid-state reaction method. The influence of Fe substitution for Ti on the crystalline structure and the magnetic property of BaTi1-xFexO3 samples were investigated. The obtained X-ray diffraction patterns showed that the structure of the material sensitively depends on Fe dopant content, x, and transforms gradually from the tetragonal (P4mm) phase to the hexagonal (P63/mmc) one with increasing x. All of the samples exhibit both ferroelectricity and ferromagnetism at room temperature. The result of magnetization measurements showed that the magnetization at a magnetic field as high as 1 T abnormally depends on x, increases with increasing x to a maximum at x=0.1 then decreases monotonously afterward. There are possibilities to account for this anomalous magnetic behavior such as the Fe3+-to-Fe4+ and/or Ti4+-to-Ti3+ change(s) induced by oxygen vacancies. The substitution of Fe into Ti sites also changes the conductivity of the material and impurity (acceptor) levels in the band gap, which can be evident from the absorption spectra, electric impedance, and timedependent leakage current measured at room temperature. Key words: Multiferroics, XRD, UV - visible spectra, magnetization, model for ferromagnetism INTRODUCTION* BaTiO3 has been well known for its ferroelectricity at room temperature, high permittivity, wide band gap, and numerous dielectric-based applications. It has also attracted great attention of basic research due to its different polymorphs, which exist at various temperature ranges: rhombohedral (T 1460 0C). Nevertheless, .