µSR Methods

• There are many other specific µSR techniques with their own acronyms. This link shows my "official" approved list. (There is also an old funky version).

• I have also proposed a convention for labelling the 3-D coordinate system (also available in a clean GIF) for µSR experiments with surface muons, which can be transmitted through a spin rotator made from a "DC separator" (also known as a Wien filter) to rotate the muon spins until they are perpendicular to their momenta. (This is essential for injecting the muons into strong transverse magnetic fields.)

• The basic method most commonly employed in µSR is shown here in a grossly oversimplified cartoon version.

• The above cartoon describes time-differential or TD-µSR, which comes in several flavours:

  • Here you can see transverse field (TF)-µSR in a bit more detail.

  • This sketch shows the two typical TF-µSR geometries.

  • This one shows zero and longitudinal field (ZF and LF) µSR.

• There are also a number of techniques based on time-Integral or I-µSR methods.

  • The basics of I-µSR are explained here and here; some rather atypical results are shown here.

  • One of the more useful branches of I-µSR is based on avoided level-crossing resonance (ALCR), which in turn comes in (at least) two flavours:

    • Quadrupolar ALCR occurs when the muon's Zeeman splitting is degenerate with a splitting between electric quadrupole energy levels of a nearby nucleus. It has been used to determine the muon site in several crystals.

    • Paramagnetic ALCR occurs when two energy levels of a µ-e-nucleus 3-spin system with opposite muon spins are degenerate. It is widely used to study muonium states in semiconductors and radicals (paramagnetic molecules) formed by chemical addition of Mu to (e.g.) unsaturated bonds of organic molecules.

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  Jess H. Brewer
  Last modified: Fri Dec 5 11:39:15 EST ±