Qauntum interfaces studied with low energy beta-NMR and muSR

由于平移对称性的破坏以及一种材料对另一种材料的影响，在两种材料之间的界面附近，材料的所有电子、磁性和结构特性都会发生改变。在某些情况下，这些变化很小，仅局限于几个原子层，而在其他情况下，行为的变化是深刻的，延伸到许多纳米。磁性多层中的巨磁电阻是一个值得注意的例子，因为这一发现对磁存储产生了巨大的影响。很少有实验方法能够以深度分辨的方式探测局部特性。我们在TRIUMF开发了一种叫做低能探测核磁共振。唯一的其他类似方法是低能μ子自旋/弛豫，这只能在瑞士的保罗·谢勒研究所（PSI）进行。这两种方法原理相似，但提供的信息是互补的。两者都可以被视为一种特殊形式的磁共振，它非常适合于薄膜和界面的研究，因为它们需要的自旋比传统的核磁共振少大约10个数量级。我们的目标是利用这些新方法探索量子材料及其界面的电子特性。

All electronic, magnetic and structural properties of a material are altered near an interface between two materials due to the broken translational symmetry and the influence that one material can have another. In some cases these changes are small and confined to just a few atomic layers while in other situations changes in behaviour are profound and extend over many nanometers. Giant magnetoresistance in magnetic multilayers is one notable example because of the large impact this discovery has had on magnetic storage. Few experimental methods are capable of probing local properties in a depth resolved manner. We have developed one of these at TRIUMF called low energy beta-detected nuclear magnetic resonance. The only other similar method is low energy muon spin rotation/relaxation which can only be performed at the Paul Scherrer Institute (PSI) in Switzerland. The two methods have similar principles but provide complementary information. Both may be regarded as a special form of magnetic resonance, which are well suited to studies in thin films and interfaces because they require roughly 10 orders of magnitude fewer spins than conventional NMR. Our goal is to explore electronic properties quantum materials and their interfaces using these novel methods.