Magnetic relaxation of mesoscopic molecules
Magnetic relaxation of mesoscopic molecules
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介观分子的磁弛豫
DOI：
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发表时间：
1998
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影响因子：
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通讯作者：
A. Würger
中科院分区：
文献类型：
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作者：
A. Würger
纳米级分子的弛豫动力学，例如来自自旋-晶格耦合和与核自旋的相互作用。使用预解式方法的能量本征态和第一玻恩近似的声子散射，并平均在超精细场，我们得到一个控制近似的非平衡磁弛豫行为，特别是相应的速率。速率在T = 0时是有限的，然后随T线性增加，并在较高温度下表现出Arrhenius行为;对于零磁场B，有两个不同的激活能。作为B的函数的共振被示出为关于B = 0略微不对称。考虑到四次晶场引起B的共振值随温度的变化。我们发现，与以前的结果相反，在低但有限的温度下，速率与磁场无关，因为它在B中是线性的。最后，我们比较了我们的研究结果与各种实验数据。
The relaxation dynamics of nanoscale molecules such as arises from spin-lattice coupling and interaction with nuclear spins. Using a resolvent method in terms of the energy eigenstates and the first Born approximation with respect to phonon scattering, and averaging over the hyperfine field, we obtain a controlled approximation for the non-equilibrium magnetic relaxation behaviour and, in particular, for the corresponding rate. The rate is finite at T = 0, then increases linearly with T, and shows Arrhenius behaviour at higher temperature; for zero magnetic field B there are two different activation energies. The resonances as a function of B are shown to be slightly asymmetric about B = 0. Taking account of a quartic crystal field gives rise to a temperature-dependent shift of the resonant values of B. We find that, contrary to previous results, the rate is independent of the magnetic field at low but finite temperatures; for it is linear in B. Finally we compare our findings with various experimental data.