An insight into formation mechanism of rapid chemical Co- precipitation for synthesizing yttrium iron garnet nano powders Junliang Liu a, * , Qimei Jin a , Shengyun Wang a , Ping Yu a , Chong Zhang a , Clark Luckhardt b , Zijuan Su b , Radhika Barua b , Vincent G. Harris b a School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China b Center for Microwave Magnetic Materials and Integrated Circuits, Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115, USA highlights graphical abstract  The elements homogeneity in pre- cursor determines the phase evolu- tion process.  Synthesis temperature decreases if tetragonal YIG exists as the interme- diate phase.  A stable technique is for synthesizing high quality cubic YIG nano powders. article info Article history: Received 13 September 2017 Received in revised form 5 December 2017 Accepted 9 January 2018 Available online 12 January 2018 Keywords: Yttrium iron garnet Nanopowders Chemical co-precipitation Phase formation abstract The rapid chemical co-precipitation method is supposed to be a stable way to synthesize high quality cubic yttrium iron garnet (YIG) nanopowders. In this paper, focusing on clarifying its formation mech- anism, the thermal behaviors and the elemental distributions of the chemical co-precipitated precursors have been analyzed by simultaneous differential scanning calorimetry plus thermal gravimetric analysis (DSC-TGA) and energy disperse spectroscopy (EDS) mapping technique on a transmission electronic microscope. The results indicated that the homogeneity of Y and Fe elemental distributions in the pre- cursor powders determines the process through which the cubic YIG phase would form: one experiences the intermediate tetragonal YIG phase; the other takes YFeO 3 as the intermediate phase. The homoge- nous distributions of Y and Fe elements in the precursor powders at the scale below 50 nm forms the intermediate tetragonal YIG phase rather than YFeO 3 , which leads to reduction of the formation tem- perature for synthesizing the single phase YIG. The obtained YIG nanopowders with the average particle size below 100 nm show excellent magnetic properties with saturation magnetization of 26 emu/g and coercive field of 45 Oe. This clear formation mechanism of YIG nanopowders is suitable for optimizing the processing conditions for the chemical precipitation synthesis of YIG nanopowders at large scale. © 2018 Elsevier B.V. All rights reserved. 1. Introduction Conventionally, yttrium iron garnet (YIG) with chemical formulation of Y 3 Fe 5 O 12 is considered to be an important soft * Corresponding author. E-mail address: liujunliang@yzu.edu.cn (J. Liu). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys https://doi.org/10.1016/j.matchemphys.2018.01.030 0254-0584/© 2018 Elsevier B.V. All rights reserved. Materials Chemistry and Physics 208 (2018) 169e176