Muon spin depolarization in a thermalized molecular ion in crystalline phase of 3He

✍ Scribed by Yu.M. Belousov

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 172 KB
• Volume: 374-375
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.11.090

✦ Synopsis

Muon spin depolarization rate is calculated for thermalized molecular ions He 2 m þ . Only 3 4 of the muon spin polarization will be depolarized if all spin states of the molecular ion He 2 m þ have the equal probability. The effective spin-hamiltonian of the ortho-ion differs for rotational states jK ¼ 1; M ¼ 0i and jK ¼ 1; jMj ¼ 1i. Different relaxation rates of the muon spin polarization is observed for these states. Relaxation processes are connected with direct magnetic dipole-dipole and spin-phonon interactions. Direct magnetic dipole-dipole interactions play the main role at temperature T41 K. At lower temperature spin-phonon interaction plays the main role.

Relaxation rates are calculated within the frame work of the Wangsness-Bloch equations in the limit of strong magnetic fields for the case of spin-phonon interaction. It is shown that depolarization rates could strongly differ for states jK ¼ 1; M ¼ 0i and jK ¼ 1; jMj ¼ 1i. A fit of experimental data by one exponent is not correct in the above mentioned case. Depolarization pattern depends on 4 He impurity concentration because thermalized molecular ions containing at least one 4 He atom have K ¼ 0 where no hyperfine interaction exists.