DYNAMIC ORBIT-LATTICE INTERACTIONS FOR PBF2-GD3+ SINGLE-CRYSTALS

Temperature dependence of the second-order spin-lattice coefficients for PbF2:Gd3+ is reported. It is shown that the thermal expansion of the crystal lattice contributes only in about 14% to the observed dependence and the rest should be ascribed to a dynamic coupling between the 4f7 electrons and lattice vibrations. The results are parametrized in both the Einstein and the Debye models and it is shown that the phenomenological parameters obtained from such parametrization can be made to coincide in both models if a specific value of the Einstein frequency omega-E is properly chosen. Both models of parameterization show that the GAMMA-3g vibrating mode couples to the 4f7 electrons much weaker than the GAMMA-5g one

Spin-Phonon Contributions to the b20\text{}_{2}^{0} Parameter for Gd3+\text{}^{3+} in RbCdF3\text{}_{3} Single Crystals

Temperature dependence of the b$\text{}_{2}^{0}$ spin-hamiltonian parameter for Gd$\text{}^{3+}$ in RbCdF$\text{}_{3}$ single crystals is described. The dependence is interpreted in terms of the 4f$\text{}^{7}$ electrons coupling to the whole phonon spectrum of the crystal. The presented data give also an insight into the dynamics of charge compensators causing a tetragonal distortion of the crystal field

Dynamic Orbit-Lattice Interactions for PbF2\text{}_{2}:Gd3+\text{}^{3+} Single Crystals

Temperature dependence of the second-order spin-lattice coefficients for PbF$\text{}_{2}$:Gd$\text{}^{3+}$ is reported. It is shown that the thermal expansion of the crystal lattice contributes only in about 14 % to the observed dependence and the rest should be ascribed to a dynamic coupling between the 4f$\text{}^{7}$ electrons and lattice vibrations. The results are parametrized in both the Einstein and the Debye models and it is shown that the phenomenological parameters obtained from such parametrization can be made to coincide in both models if a specific value of the Einstein frequency ω$\text{}_{E}$ is properly chosen. Both models of parametrization show that the Γ$\text{}_{3_{g}}$ vibrating mode couples to the 4f$\text{}^{7}$ electrons much weaker than the Γ$\text{}_{5_{g}}$ one

SPIN PHONON CONTRIBUTIONS TO THE B(2)(0) PARAMETER FOR GD3+ IN RBCDF3 SINGLE-CRYSTALS

Temperature dependence of the b2(0) spin-hamiltonian parameter for Gd3+ in RbCdF3 single crystals is described. The dependence is interpreted in terms of the 4f7 electrons coupling to the whole phonon spectrum of the crystal. The presented data give also an insight into the dynamics of charge compensators causing a tetragonal distortion of the crystal field

Parametrization of the Vibronic Contributions to the b40\text{}\text{}_{4}^{0} Spin-Hamiltonian Parameters for 8\text{}^{8}S7/2\text{}_{7}\text{}_{/}\text{}_{2} Ground State Ions in Fluoroperovskites

Parametrization of phonon induced contributions to the experimentally determined temperature dependence of the b$\text{}_{0}^{4}$ spin-Hamiltonian parameter for Gd$\text{}_{3+}$ doped RbCaF$\text{}_{3}$, CsCaF$\text{}_{3}$, RbCdF$\text{}_{3}$ and TlCdF$\text{}_{3}$ single crystals is discussed. Three physically different parametrization schemes are considered, i.e. that of Einstein, Debye and Huang. It is found that the model of Huang, which predicts that the phonon induced contributions should be proportional to the Debye-Waller factor, describes best the experimental data. The method allowing determination of the Debye temperature from EPR data is also suggested