准一维反铁磁体CsMnCl3·2D2O中激子的能量转移

在2—300K温度范围,研究了纯的及掺Mg²⁺,Ni²⁺和Co²⁺的准一维反铁磁体CsMnCl₃·2D₂O(CMC)中Mn²⁺离子的⁴T₁激子的能量转移动力学过程,发现在2—10K范围,激子的荧光强度和寿命随温度很快下降,较高浓度的杂质离子将进一步加快荧光的减弱和寿命的缩短。这种现象被归结为与磁相互作用和自旋有序相关联的多声子无辐射跃迁及施主—受主之间的能量转移。在更高的温度,能量转移速率增高,但由于仍然存在的自旋短程有序和Jahn-Teller效应,施主之间的能量迁移受到一定限制,出现非指数衰减过程。各种不同的杂质离子在某种程度上显示出不同的陷落作用和弛豫特性。关键词：

ENERGY TRANSFER OF THE EXCITON IN THE QUASI-ONE-DIMENSIONAL ANTIFERROMAGNET CsMnCl3·2D2O

The dynamic processes, of energy transfer of the ⁴T₁ exciton of Mn²⁺ ions have been studied in the temperature region 2-300 K in the pure and Mg²⁺-, Ni²⁺-, Co²⁺-doped quasi-one-dimensional antiferromagnet CsMnCl₃·2D₂O (CMC). It has been found that the fluorescent intensity and the lifetime of the exciton drops rapidly with increasing temperature in the region 2-10 K, with a further weakened fluorescence and shortened lifetime in the heavily doped crystals. These phenomena are presumed to be associated with the multiphonon nonradiative transition and energy transfer between donors and acceptors, both of which are related to the magnetic interactions and the spin ordering. At higher temperature, the rate of energy transfer increases. However, because of the persistence of spin short-range order and the Jahn-Teller effect, the energy transfer among donors is still limited to some extent, and nonexponential attenuation processes appear. The different impurities show different abilities of trapping and relaxing to a certain degree.