Mn²⁺ and the trivalent europium (Eu³⁺)-doped MgGa₂O₄ ceramics are characterized using a multi-experimental approach. The formation of spinel-structured ceramics is ascertained from X-ray diffraction (XRD) analysis. Morphology investigations with transmission electron microscopy (TEM) show irregularly shaped grains and grain boundaries with a homogeneous distribution of Eu³⁺ ions. The inability of Eu activator to penetrate the bulk of ceramic grains is inferred from positron annihilation lifetime spectroscopy data. The Eu doping is shown to enhance the positron trapping rate due to the occupancy of vacancy-type defects at ceramic grains by Eu³⁺ ions. Both Mn²⁺ and Eu³⁺ doped samples show a broad multi-color luminescence in 350–650 nm range under 240 nm and 270–300 nm excitations. Blue emission is concluded to originate from host defects, whereas green emission and narrow lines in the red region of the spectrum are attributed to Mn²⁺ and Eu³⁺ ions, respectively. High asymmetry around Eu³⁺ ions can be concluded from the photoluminescence and positron annihilation lifetime spectra analysis.

中文翻译：

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Eu 3+活化MgGa 2 O 4：Mn 2+陶瓷荧光粉的微观结构和发光性能

Mn ²⁺和三价euro（Eu ³⁺）掺杂的MgGa ₂ O ₄陶瓷的特征在于采用多实验方法。尖晶石结构的陶瓷的形成是通过X射线衍射（XRD）分析确定的。用透射电子显微镜（TEM）进行的形态学研究表明，不规则形状的晶粒和晶界具有均匀分布的Eu ³⁺离子。从正电子an没寿命光谱数据可以推断出Eu活化剂无法穿透大部分陶瓷晶粒。由于Eu ³⁺离子在陶瓷晶粒上占据了空位型缺陷，因此Eu掺杂可提高正电子俘获率。Mn ^2+均掺杂Eu ^3+的样品在240 nm和270-300 nm激发下在350-650 nm范围内显示出较宽的多色发光。结论是蓝色发射源于主体缺陷，而光谱的红色区域中的绿色发射和窄线分别归因于Mn ²⁺和Eu ³⁺离子。从光致发光和正电子an没寿命光谱分析可以得出Eu ³⁺离子周围的高度不对称性。