Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
ACS Nano. 2012 Sep 25;6(9):8390-6. doi: 10.1021/nn3031673. Epub 2012 Sep 5.
We present measurements of the magnetic properties of thin film TbPc(2) single-molecule magnets evaporated on a gold substrate and compare them to those in bulk. Zero-field muon spin relaxation measurements were used to determine the molecular spin fluctuation rate of TbPc(2) as a function of temperature. At low temperature, we find that the fluctuations in films are much faster than in bulk and depend strongly on the distance between the molecules and the Au substrate. We measure a molecular spin correlation time that varies between 1.4 μs near the substrate and 6.6 μs far away from it. We attribute this behavior to differences in the packing of the magnetic cores, which change gradually on the scale of ~10-20 nm away from the TbPc(2)/Au interface.
我们展示了在金基底上蒸镀的 TbPc(2) 单分子磁体薄膜的磁性能测量结果，并将其与体相进行了比较。零场μ子自旋弛豫测量被用来确定 TbPc(2) 的分子自旋涨落率随温度的变化关系。在低温下，我们发现薄膜中的涨落速度比体相快得多，并且强烈依赖于分子与 Au 基底之间的距离。我们测量了分子自旋关联时间，它在靠近基底的位置约为 1.4 μs，在远离基底的位置约为 6.6 μs。我们将这种行为归因于磁性核的堆积方式的差异，这种差异在距离 TbPc(2)/Au 界面约 10-20nm 的范围内逐渐发生变化。
