A correlation of lattice distortion with the magnetic properties of calcium doped bismuth ferrite thin films

Abstract

In this work, Bi1−x Ca x FeO3 (for x = 0.00–0.30) single-phase thin films were developed on clean glass substrates via simple spray pyrolysis technique. The microscopic crystal structure and magnetic characteristics of the Ca modified thin films were investigated. X-ray diffraction study confirms the hexagonal structure with the space group R3c for all the prepared thin film samples. The crystallite sizes and lattice strains were computed by using the Williamson–Hall plot. The morphology of the samples was viewed by field emission scanning electron microscopy which shows that the average size of grains systematically decreases with the addition of Ca atom at Bi site. The compositions of samples were confirmed by using energy dispersive spectroscopy. The structural phase transition and the position of different Raman modes were observed by using the Raman spectroscopy technique. The elementary compositions, different oxidation states, and the effect of oxygen vacancies of the elements were observed by x-ray photoelectron spectroscopy. The magnetic field (H) dependence of magnetization (M) (i.e. M–H hysteresis loops) of the pure bismuth ferrite (BFO) and Ca doped BFO thin film samples conducted at room temperature using a vibrating sample magnetometer with an applied magnetic field of ±30 kOe and confirmed that the value of magnetization significantly increases with Ca addition at Bi-site in BFO atom. The maximum value saturation magnetization of 3.8176 emu g−1 and remanent magnetization of 0.1408 emu g−1 obtained for the 25% Ca doped BFO thin films.

In situ Raman investigation of the phase transition of NaVO2F2 under variable temperature conditions

“…For example, Raman spectroscopy is used to analyze the structural changes of substances aer doping elements. [8][9][10] Furthermore, Raman spectroscopy is also used in medical systems to detect cancer, diseases related to the human nervous system and other diseases. [11][12][13][14][15] However, in situ Raman spectroscopy can more accurately characterize the transformation law of the structural characteristics of the objects.…”

Unusual Behavior of Magnetic Coercive Fields with Temperature and Applied Field in La-Doped BiFeO3 Ceramics

“…The utilization of bulk BFO in functional applications is consequently restricted by these issues. Recently, many researchers have shown that rare-earth elements , or alkaline-earth elements , doping at the A site, as well as partial replacement of B site ions by metal elements from the transition group, , are effective ways to unlock the spiral structure and enhance the magnetic characteristics of BFO. According to the previous reports, the magnetism and ferroelectricity of BFO were increased when Bi and Fe were partially substituted at the same time by ions like Er and Nb, Sr and Mn, Dy and Mn, etc.…”