Measurement of electron spin flip-flop time

我们测量了红宝石中~lt；Cr^(3+)&gt；基态的(+1/2)能级电子自旋的触发时间。(Phys.Rev.B34.1972，‘86)这是世界上第一个直接测量二能级电子自旋系统触发时间的实验。在本实验中，我们使用了我们在同一电子自旋系统中提出并检验的光学标记方法。(Phys，Rev.B30 2983，‘84)在外加磁场下约为10秒(0.05wt%)，高于500 Oe。这比A.Szabo通过间接测量获得的报告值要长。造成这种差异的原因一直没有人弄清楚。我们需要更精确地测量浓度和磁场相关性。我们还研究了固体中稀薄自旋体系交叉弛豫时间的理论计算。B29.6043，‘84)我们提出了自旋触发时间的时间依赖关系，它将与~lt；t^(-1/2)&gt；成正比。理论和实验研究表明，描述二能级自旋系统的Bloch方程并不总是正确的。在均匀线宽的饱和度和形状上，实验结果与理论预期的差异变得明显。(光学通讯，51,163，‘84)这种差异的原因归因于非纯的二能级系统。由于周围顺磁原子核之间的超超临界相互作用，它伴随着许多子能级。我们在外加磁场下测量了稀红宝石中&lt；R_1&gt；谱线成分的均匀谱线展宽，并用上述观点对结果进行了解释。

We have measured the flip-flop time of electron spins in the (+1/2)sublevels of the ground state <^4A_2> of <Cr^(3+)> in ruby. (Phys.Rev.B34.1972,'86) It is the first experiment in the world to measure directly the flip-flop time of a two-level elctron spin system. In this experiment, we used the method of optical labeling, which is proposed and examined by us in the same electron spin system. (Phys,Rev. B30 2983,'84) It is about 10 sec ( 0.05 wt% ) at the applied magnetic fields, higher than 500 Oe. It is longer than the reported value by A.Szabo obtained by indirect measurment. The cause of the difference has never been understood. We need much more precise measurements of concentration and magnetic field dependence. We also investigated the theoretical calculation of cross relaxation time in dilute spin system in solids.(Phys. Rev.B29.6043,'84) We porposed the time dependence of the spin flip-flop time, which will be proportional to <t^(-1/2)> .Theoretical and experimental investigation to show that Bloch equations to describe a two-level spin system are not always correct. In the saturation and the shape of homogeneous line broadening, differences between the experimental results and the theoretical anticipations become clear. (Optics Commun.51,163,'84) The cause of the differences is attributed to non-pure two level system. which is accompanied by many sublevels due to superhyperfyne interaction between surrounding paramagnetic nuclei. We have measured homogeneous line broad-ening of -components of <R_1> line in a dilute ruby at applied magnetic fileds and results are explained by the same idea reported above.