Muons spin relaxation

The muon spin relaxation technique uses the implantation and subsequent decay of muons, n+, in matter. The muon has a polarized spin of 1/2 [22]. When implanted, the muons interact with the local magnetic field and decay (lifetime = 2.2 ps) by emitting a positron preferentially in the direction of polarization. Adequately positioned detectors are then used to determine the asymmetry of this decay as a function of time, A t). This function is thus dependant on the distribution of internal magnetic fields within a... 

Kiefl RF, MacFarlane WA, Chow KH, Dunsiger S, Duty TL, Johnston TMS, Schneider JW, Sonier J, Brard L, Strongin RM, Fischer JE, Smith AB 111 (1993) Coherence peak and superconducting energy gap in Rb3Cgo observed by muon spin relaxation. Phys Rev Lett 70 3987-3990... 

Ohira S, Shimizu Y, Kanoda K, Saito G (2006) Spin liquid state in k-(BEDT-TTF)2Cu2(CN)3 studied by muon spin relaxation method. J Low Temp Phys 142 153-158... 

The response for low doping closely follows a two-fluid type behaviour for low hole doping but which deviates from this at higher doping levels. Schneider and Keller [26] analysed Muon spin relaxation rate o- data and noted universal trends in the reduced transition temperature T for a series of extreme type II superconductors which includes the cuprates and the reduced muon spin relation rate [Pg.300]

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... 

Keywords Fullerenes Ferromagnetism Jahn-Teller effect Magnetic resonance Muon spin relaxation Structural properties Orbital ordering... 

Figure 3 Variation of Tc with hole concentration nh in superconducting cuprate families (adapted from reference 15). Deviations in overdoped region are similar to those in the plots of muon spin relaxation rate against Tc of UemUra et al. (Phvs. Rev. Lett, 1991, 66,...

The experimental situation is inconclusive and sometimes even the same experimental techniques used by different groups give contrary results. Especially for the compounds k-(ET)2Cu(NCS)2 and K-(ET)2Cu[N(CN)2]Br many different techniques have been employed to measure A(T). Evidence for non BCS-like behavior has been obtained by complex ac susceptibility [220], radio-frequency penetration depth [221], muon spin relaxation (//SR) [222], and microwave surface impedance measurements [223]. In contrast, results consistent with conventional BCS theory, sometimes revealing a tendency towards strong coupling, are reported for measurements of the //SR [224], microwave surface impedance [225, 226], and dc magnetization [227]. 

The role of anisotropy and interchain interaction has been identified through dc and ac conductivity of stretch films, Kramers-Kronig analysis of reflectance on stretched films, anisotropic microwave frequency conductivity [44,52] and muon spin relaxation [62]. The role of interaction of spin of interstitial dopants with the conduction electrons at low temperatures has recently been explored by Y.W. Park and coworkers [63]. 

Ue91 Y. J. Uemura e< al, Magnetic-Field Penetra tion Depth in K3C60 Measured by Muon Spin Relaxation, Nature 352, 605-607 (1991). 

Muon spin relaxation (/u.SR) has been employed in determining the rate constants and Arrhenius parameters for the addition of the ethyl radical and the t-butyl radical to... 

A relatively new technique which is being increasingly applied to the study of magnetic materials is that of muon spin rotation [jliSR also known as muon spin relaxation or resonance (Schenck 1985)]. In the most common arrangement a beam of spin polarized muons ju,+ (say) is directed towards and stopped in a target. The anisotropy in the ju, - e decay rate (e.g., from a comparison of the rate in backward and forward directions) is monitored as a function of elapsed muon lifetime for a large number of stopped muons. The basic equation on which the technique is based is... 

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