2006/07/04 by Yuriy V. Sereda, Y. Sereda, I. Ya. Polishchuk +2 · 7 citations
Materials Science · Physics and Astronomy · #Condensed matter physics #Dielectric #Glass properties and applications #Magnetic field #Nuclear quadrupole resonance #Physics #Quantum mechanics #Quantum optics and atomic interactions #Quantum tunnelling #Relaxation (psychology) #Solid-state spectroscopy and crystallography #Zeeman effect #Zeeman energy #cond-mat.dis-nn
paper · pdf · doi:10.1103/physrevb.75.024207
published in Physical Review B 75(2) (American Physical Society) · 9 Pages, 5 Figures, To be submitted to the Physical Review B, please send comments
arxiv created 2006/07/04 · openalex publication_date 2007/01/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider the anomalous magnetic field dependence of dielectric constant of insulating glasses at temperatures 10\phantom\rule0.3em0exmK<T<50\phantom\rule0.3em0exmK. In this temperature range, the dielectric permittivity is determined by the resonant contribution of tunneling systems. In the external magnetic field nuclear spins of tunneling atoms acquire the Zeeman energy. This interaction competes with a nuclear quadrupole interaction and, thus, affects tunneling system energy statistics. Consequently the dielectric response of tunneling systems depends on the magnetic field. It is demonstrated that in the absence of an external magnetic field the nuclear quadrupole interaction b results in a correction to the permittivity \ensuremathδ\ensuremathχ\ensuremath∼\ensuremath|b\ensuremath|∕T in the temperature range of interest T>b. An application of a magnetic field results in a sharp increase of this correction approximately by a factor of 2 when the Zeeman splitting m approaches the order of \ensuremath|b\ensuremath|. A further increase of the magnetic field results in a relatively smooth decrease of this correction until the Zeeman splitting approaches the value of T. This smooth dependence results from tunneling accompanied by a change of the nuclear spin projection. As the Zeeman splitting surpasses T, the correction vanishes. The results are compared with experiment. A new mechanism of the low-temperature nuclear spin-lattice relaxation in glasses is discussed.