YAG晶体色心的EPR谱

本文描述了8种YAG样品的室温和77K的EPR谱.从这些谱的参数与光谱的实验数据对照,认为晶体中有三种顺磁性的色心,其中g～2.00和g～1.98两条顺磁谱相应于光谱2×10~4cm~(-1)～3.4×10~4cm~(-1)的吸收带,为YAG基质晶体中的缺陷俘获一个电子构成的电子型缺陷中心;而 g～30.60的顺磁谱线与氧空位和掺杂的金属离子Mg~(2+) 、Cr~(3+)有关,推测为氧空位团或氧空位与金属离子构成的S>1/2的复合顺磁中心缺陷.YAG晶体随着在大气氛中高温退火,氧的进入和金属离子的掺入,造成电子和空间体积的不平衡,从而使晶体色心浓度加大.

EPR spectra of colour centres in YAG crystals

In this paper, EPR spectra of eight olassaele YAG crystals at room temperature and 77K have been described. Based on data of EPR and optical spectra, three paramagnetic colours exoisting in crystals are suggested. Two EPR spectra with g-2 and g-1.98 are corresponding to 2xxxxxxxxxxxxxxl04cm-1-3.4xxxxxxxxxxxxxxxl04cm-1 bands of optical absorption spectra. These gpeotra are originated from the defect centres of electronic type when the defect capturing one electron in YAG crystals. The other EPR spectrum with g-3.6 depends on oxygen vaoaocies and doped with metallic ions Mg2+ and Or3+. The author supposed that it is a complex paramagnetic defect centre of S>1/2, consisting of an oxygen vacancy or its group and metallic ions. When YAG crystals doped with metallic ions and annealed in high temperature atmospheric, the colour centre concentration increases, which is caused by out of balance on the electron and volume in crystals.