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本文讨论了工作[3]中决定耦合系统磁化系数的方法,并用来分析自旋-晶格弛豫过程。在弱耦合的情况下,得出了决定磁化系数的耦合方程组,并求出纵向非共振吸收和横向共振吸收线型的表达式。得出的纵向和横向弛豫时间是外加交变场频率的函数,这反映了高频场对弛豫的影响是由于所用密度矩阵方程为非马尔科夫型的直接结果。在远离共振点处,所得的线型公式和德拜型或洛仑兹型差别较大。一般说来,非马尔科夫效应是不能忽略的。在自旋S=1的情况,我们系统地分析了纵向及横向弛豫的基本过程。其中包含与通常讨论的过程相应的项,如单声子过程,Raman过程,Orbach过程等等,但现在都有外加交变场频率ω参与进去。最后讨论了声子的寿命对横向弛豫时间的影响。The method used in Ref. [3] to treat the magnetic susceptibility of the coupled system was extended to analyse the spin-lattice relaxation processes. In the case of weak coupling, the detailed expressions for the line shape of longitudinal nonresonance absorption and transverse resonance absorption were obtained by solving a set of coupled equations. The longitudinal and transverse relaxation times have been obtained as functions of the external alternating field. This is the direct consequence of the fact that the equations we used are of the non-Markovian type. Far away from the resonance point, the actual expression of the line shape is found to be quite different from that of the Debye or Lorentz type; the non-Markovian effect generally can not be ignored.In the case of S = 1, all the processes involved in the expressions of longitudinal and transverse relaxation times were systematically analysed. It is found that some terms correspond to the usually discussed processes such as one phonon process; the Orbach process, etc., but involve the frequency as a parameter as mentioned above. The influence of lifetime of phonons on the transverse spin-lattice relaxation was also discussed.
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