| abstract |
A starting material powder, which contains a rare earth oxide that is composed of terbium oxide and at least one other rare earth oxide selected from among yttrium oxide, scandium oxide and oxides of lanthanide rare earth elements (excluding terbium) and a sintering assistant that is formed of an oxide of at least one element selected from among group 2 elements and group 4 elements, is produced by having (a) terbium ions, (b) ions of at least one other rare earth element selected from among yttrium ions, scandium ions and lanthanide rare earth ions (excluding terbium ions) and (c) ions of at least one element selected from among group 2 elements and group 4 elements coprecipitate in an aqueous solution containing the components (a)-(c), then filtering and separating the coprecipitate, and subjecting the separated coprecipitate to thermal dehydration. |