Muon-induced effects

We have already pointed out the possibility of muon-induced effects in sect. 2.4, in general terms. In the last section evidence for the actual occurrence of such effects... 

Muon-induced effects are sometimes invoked in a number of heavy-fermion and related systems where jxSR led to the worrisome discovery of anomalously small but non-zero magnetic moments (see sect. 9). In some instances these moments are below 10 Ub, which makes them undetectable by other methods, except by resonant photon scattering in the light actinides. Full confirmation of small moments first detected by [xSR occurred in cases where those moments had reached a size (pi w 510" Ub) accessible to neutron scattering under favorable conditions. So, extremely small moment magnetism is in all likelihood an intrinsic property of many heavy-fermion compoimds. 

PrCu2- Anomalies in the field dependence of the Knight shift and an excessive ZF dipolar width in this singlet ground state system have been considered to arise from muon-induced effects (Schenck et al. 1997a). The case is presented in sect. 5.1. 

Snider is best known for his paper reporting what is now referred to as the Waldmann-Snider equation.34 (L. Waldmann independently derived the same result via an alternative method.) The novelty of this equation is that it takes into account the consequences of the superposition of quantum wavefunctions. For example, while the usual Boltzmann equation describes the collisionally induced decay of the rotational state probability distribution of a spin system to equilibrium, the modifications allow the effects of magnetic field precession to be simultaneously taken into account. Snider has used this equation to explain a variety of effects including the Senftleben-Beenakker effect (i.e., is, the magnetic and electric field dependence of gas transport coefficients), gas phase NMR relaxation, and gas phase muon spin relaxation.35... 

The cosmic radiation incident on the earth is generated in our galaxy. It is effectively absorbed in the atmosphere, and the flux density is reduced from about 20 cm s to about 1 cm" s at the surface of the earth. By interaction with the atoms and the molecules in the atmosphere showers of elementary particles are produced, making up the secondary cosmic radiation. Positrons, muons, several kinds of mesons and baryons were first detected in the secondary cosmic radiation. Furthermore, nuclear reactions induced by secondary cosmic radiation lead to the production of cosmogenic radionuchdes, such as T and (section 1.2). 

There are many experimental techniques for the determination of the Spin-Hamiltonian parameters g, Ux, J. D, E. Often applied are Electron Paramagnetic or Spin Resonance (EPR, ESR), Electron Nuclear Double Resonance (ENDOR) or Triple Resonance, Electron-Electron Double Resonance (ELDOR), Nuclear Magnetic Resonance (NMR), occasionally utilizing effects of Chemically Induced Dynamic Nuclear Polarization (CIDNP), Optical Detections of Magnetic Resonance (ODMR) or Microwave Optical Double Resonance (MODR), Laser Magnetic Resonance (LMR), Atomic Beam Spectroscopy, and Muon Spin Rotation (/iSR). The extraction of data from the spectra varies with the methods, the system studied and the physical state of the sample (gas, liquid, unordered or ordered solid). For these procedures the reader is referred to the monographs (D). Further, effective magnetic moments of free radicals are often obtained from static... 

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