Two kinds of polymer-metal compounds, heterogeneous complexes (metal-chelating copolymer microspheres, MCP) and homogeneous complexes (water-soluble metal-chelating polymers, WSMCP), were synthesized to act as nucleation agents for YIG precursor preparation in this text. Both of the metal-chelating polymers have the same chelating group and high metal ion adsorption ability from the FTIR and ICP measurement. Furthermore, good YIG crystals can be obtained by treating the MCP precursor with a low calcination temperature at 600 degrees C from the XRD spectra and TEM micrograph. However, the YIG crystal obtained using a WSMCP precursor should be synthesized at a higher calcination temperature (> 900 degrees C) due to the different components of the YIG precursor. In addition, the YIG crystal obtained by using the MCP precursor had nearly superparamagnetic behavior after VSM examination. (c) 2006 Elsevier Inc. All rights reserved.