Temperature Dependence of the Crystal-Field Splittings in Gd3+:CaWO4

1971 ◽  
Vol 49 (8) ◽  
pp. 995-1003 ◽  
Author(s):  
J. S. M. Harvey ◽  
H. Kiefte

The spin-Hamiltonian parameters for Gd3+ in CaWO4 have been measured by the method of electron spin resonance at a number of temperatures between 4.2 °K and 300 °K. The results at 78 °K are in agreement with previous measurements by Hempstead and Bowers.The variations in the crystal-field parameters are interpreted in terms of a limiting low temperature value and a normalized slope at the Debye temperature for each parameter. These quantities are compared with the corresponding quantities for Eu2+ in CaWO4 and, in the case of the fourth-order parameters, for Eu2+ and Gd3+ in cubic CaF2, SrF2, and BaF2. We conclude that the second- and fourth-order splittings each arise from at least three competing mechanisms and that these include a dependence on the amplitude of lattice vibrations. In the case of the trivalent ion, Coulomb forces are also considered to be important.

1967 ◽  
Vol 45 (8) ◽  
pp. 2769-2777 ◽  
Author(s):  
A. Manoogian ◽  
J. A. MacKinnon

The electron spin resonance spectrum of the vanadyl ion VO2+ is studied in single crystals of RbAl(SO4)2.12 H2O and CsAl(SO4)2.12 H2O, at room temperature and in the 9.2 kMc/s microwave frequency range. In RbAl(SO4)2.12 H2O the V–O axes are found to have three orientations directed along the cubic crystallographic axes, giving rise to three magnetic complexes. The spin Hamiltonian parameters are S = 1/2, [Formula: see text], [Formula: see text], [Formula: see text] cm−1, and [Formula: see text] cm−1. In CsAl(SO4)2.12 H2O the V–O axes are displaced from the crystallographic axes, giving rise to 12 magnetic complexes. The spin Hamiltonian parameters are S = 1/2, [Formula: see text], [Formula: see text], [Formula: see text] cm−1, and [Formula: see text] cm−1. The observed spectra are attributed to a vanadyl pentahydrate complex (VO2+.5 H2O) associated with a water-molecule vacancy.


1968 ◽  
Vol 46 (7) ◽  
pp. 807-810 ◽  
Author(s):  
Carl V. Stager

The electron spin resonance of Mn2+ impurities has been investigated in single crystals of Cd2V2O7. The spin-Hamiltonian parameters are gx = 2.0004(8), gy = 1.9995(8), gz = 2.0001(8), b20 = −419(1)g, b22 = 125(2)g, Ax = −86.7(3)g, Ay = −87.0(10)g, and Az = −87.4(5)g. The results have been compared with similar studies on isomorphic crystals and with a calculation employing the point-charge model for the crystal field. The model gives reasonable agreement with the experimental results.


2004 ◽  
Vol 59 (7-8) ◽  
pp. 488-490
Author(s):  
Manu Jain

Electron spin resonance of VO2+ doped in LiKSO4 single crystals has been studied at 295 K, using an X-band spectrometer. Three sites have been observed. VO2+ enters the lattice at Li and K substitutional sites. The ESR spectra have been analysed and spin-Hamiltonian parameters evaluated. PACS: 76.30 F


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