Formation of Sr <sub>2</sub> Si <sub>5</sub> N <sub>8</sub> :Eu <sup>2+</sup> and Its Transformation to SrSi <sub>6</sub> N <sub>8</sub> :Eu <sup>2+</sup> Controlled by Temperature and Gas PressureShin‐Mou Wu, Ru‐Shi Liu, Chi‐Hsing Hsieh et al.|Journal of the American Ceramic Society|2015Cited by 4