Difference between revisions of "Static Zero Field Relaxation"

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(Created page with "Relaxonomy --> here ---- By convention we define the muon spin polarization <math>\vec{P}</math> to be initially in the <math>z</math> direction when there is no applied...")
 
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By convention we define the muon spin polarization <math>\vec{P}</math> to be initially in the <math>z</math> direction when there is no applied magnetic field ('''ZF'''). The relaxation of <math>\vec{P}</math> is then described by
By convention we define the muon spin polarization <math>\vec{P}</math> to be initially in the <math>\hat{z}</math> direction when there is no applied magnetic field ('''ZF'''). The relaxation of <math>\vec{P}</math> is then described by
<center><math> g_{zz}(t) \; \equiv \; \langle P_z(0) \, P_z(t) \rangle \; , </math></center>
<center><math> g_{zz}(t) \; \equiv \; \langle P_z(0) \, P_z(t) \rangle \; , </math></center>



Revision as of 11:34, 13 September 2022

Relaxonomy --> here


By convention we define the muon spin polarization <math>\vec{P}</math> to be initially in the <math>\hat{z}</math> direction when there is no applied magnetic field (ZF). The relaxation of <math>\vec{P}</math> is then described by

<math> g_{zz}(t) \; \equiv \; \langle P_z(0) \, P_z(t) \rangle \; , </math>

where the lower case <math>g_{zz}(t)</math> denotes the static case of the more general <math>G_{zz}(t)</math> relaxation function.

Like "relaxation" in TF, this formulation suffers from several assumptions that are frequently invalid: first, that the average local magnetic field <math>\langle \vec{B_\mu} \rangle</math> at the muons is also zero; second, that any random local magnetic fields (RLMF) <math>\vec{B_\mu}</math> are distributed uniformly about zero in all three directions. The first assumption is not true for a magnetized ferromagnetic crystal, for example, and the second is probably not true in any single crystal environment with RLMF. In such cases this description is strictly invalid, but people use it as an approximation anyway.