Electron Spin Relaxation of Cu(II) Ions in ZnGeF_6·6H_2O Crystal with Strong Jahn-Teller Effect

• Authors: S. Idziak , S. Hoffmann , J. Goslar
• Languages of publication: EN

Abstracts

EN

Cu^{2+} ions doped to ZnGeF_6·6H_2O substitute the host Zn^{2+} ions and undergo a strong Jahn-Teller effect producing nearly axial elongation of the Cu(H_2O)_6 octahedra with equal population of the three possible deformations at low temperatures as shown by the EPR spectra. Reorientations between these distorted configurations are observed as a continuous shift of EPR lines leading to averaging of the g- and A-tensors. The full averaging is observed at the phase transition temperature 200 K. Electron spin relaxation was measured up to 45 K only, where the electron spin echo signal was detectable. Electron spin-lattice relaxation is governed by the Raman two-phonon process allowing to determine the Debye temperature asΘ_D=99 K. There is no contribution of the Jahn-Teller dynamics to the spin-lattice relaxation rate. Electron spin echo decay is strongly modulated by dipolar coupling to the ^1H and ^{19}F nuclei. The phase memory time is governed by instantaneous diffusion at helium temperatures and then by spin-lattice relaxation processes and excitation to the first vibronic level of energyΔ=151 cm^{-1}.

Keywords

EN

63.90.+t; 76.30.-v

Discipline

• 63.90.+t: Other topics in lattice dynamics (restricted to new topics in section 63)
• 76.30.-v: Electron paramagnetic resonance and relaxation(see also 33.35.+r Electron resonance and relaxation in atomic and molecular physics; 87.80.Lg Magnetic and paramagnetic resonance in biological physics)

• Journal: Acta Physica Polonica A
• Year: 2005
• Volume: 108
• Issue: 1
• Pages: 177-185

Dates

published

2005-07

received

2005-04-24

Contributors

author

S. Idziak

• Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland

author

S. Hoffmann

• Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland

author

J. Goslar

• Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland

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Identifiers

DOI

10.12693/APhysPolA.108.177