Improving Dy , Ce , Bi : YIG phase formation and magnetic features via heat treatment and chemical composition

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Improving Dy, Ce, Bi:YIG phase formation and magnetic features via heat treatment and chemical composition M. R. Khalifeh1 · H. Shokrollahi1 · F. Shahriari Nogorani2 · M. Basavad1 Received: 5 June 2020 / Accepted: 8 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract This paper focuses on the effect of Dy-substitution on the magnetic and structural behavior of Ce, Bi:YIG. In the current work, ­Fe2O3, ­Y2O3, ­CeO2 and D ­ y2O3 fine powders were mixed at a stoichiometric portion and annealed at various temperatures from 1000 to 1420 °C in the air condition for different cycle times from 27 to 33 h. The phase identification, morphological study and magnetic performance were investigated using the Raman Spectroscopy (RS) and Fourier-Transform Infrared Spectroscopy (FTIR), X-ray diffraction analysis (XRD), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM), respectively. The X-ray diffraction pattern of ­Y2.55−xDyxCe0.25Bi0.20Fe5O12 (x = 0.2, 0.4, 0.6) (Sample A) confirms the impurity phase ­CeO2. This category indicates that only a partial substitution of the Ce element is incorporated into the structure. For this reason, the ratio of the oxides and the heat treatment cycle were changed. The results revealed that the amount of C ­ eO2 phase decreases for the Sample B ­(Y2.7−xDyxCe0.15Bi0.15Fe5O12, x = 0.2, 0.4, 0.6, 0.8). To investigate the probability of a lower formation of the impurity phase ­(CeO2), the Sample C ­(Y2.8−xDyxCe0.10Bi0.10Fe5O12, x = 0.2, 0.4, 0.6) with the lower amounts of Bi and Ce cations was considered. The data revealed that the amount of impurity phase slightly decreases as a result of the large ionic radii of Bi, Ce and Dy. The magnetic coercivity (Hc) was reduced from 25.06 for Sample B to 17.78 Oe for Sample C due to a reduction in the Bi and Ce elements and C ­ eO2 impurity phase as well. The saturation magnetization ascended from 31.47 for pure YIG to 35.15 emu/g for Sample B and to 33.76 emu/g for Sample C with the same value of the Dy content (xDy = 0.2). Keywords  Calcination · Solid state reaction · Magnetic properties · Ferrites · X-ray methods

1 Introduction The yttrium iron garnet (YIG) was first developed by Forrat and Bertaut [1]. Its crystalline properties and ferrimagnetism were investigated by Geller and Gilleo [2]. YIG ­(Y3Fe5O12) is often employed in electronic devices including oscillators, isolators, circulators and phase shifters for the microwave band such as sensors, lasers, storage units, phosphorescent sources, and electrochemical devices. Its frequent use is due to its electromagnetic properties such as great Faraday rotation, low propagation loss, moderate thermal * H. Shokrollahi [email protected] 1



Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz, Iran



Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz, Iran

2

expansion coefficient, controllable saturation magnetization, high energy transfer perf