ELECTRON PARAMAGNETIC RESONANCE STUDIES OF (VO4)+2 IONS DOPED IN REDUCED Pb10-xCax(VO4)1(PO4)5(OH)2 APATITES [x = 0.0, 2.0, 4.0, 6.0, 8.0, AND 10.0]

2009 ◽  
Vol 23 (16) ◽  
pp. 3369-3389
Author(s):  
M. IKRAM ◽  
R. AMBARDAR ◽  
A. M. ROSSI ◽  
J. G. EON
Keyword(s):  
Esr Spectroscopy ◽  
Lattice Relaxation ◽  
Esr Spectra ◽  
Hydrogen Gas ◽  
Spin Lattice Relaxation ◽  
Paramagnetic Resonance ◽  
Spin Lattice ◽  
The Stability ◽  
Calcium Doping ◽  
Electron Paramagnetic

Polycrystalline solid solution of phosphate and vanadate lead calcium apatites Pb 10 -x Ca x( VO 4)1( PO 4)5( OH )2 apatites [x = 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0] was reduced with hydrogen gas at the temperature of 300 and 400°C for 1 h. All these compounds were investigated by XRD and ESR spectroscopy. Only one reduced oxidation state V +4 was detected. Two types of species like isolated vanadium (+4) and clusters of V 4+ had been observed. The stability of the apatites increases and the particle size of the crystal decreases with calcium doping concentrations. As the concentrations of Ca increase the intensity of ESR lines deviates due to the spin–lattice relaxation interactions. The deviation in the intensity of ESR spectra can be attributed as the coexistence of paramagnetic and antiferromagnetic phases in the apatites.

Electron paramagnetic resonance and spin-lattice relaxation in two-dimensional systems

1995 ◽  
Vol 8 (2) ◽  
pp. 319-333 ◽  
Author(s):  
A. Niang ◽  
G. Ablart ◽  
J. Pescia ◽  
Y. Servant ◽  
R. Duplessix ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Two Dimensional ◽  
Paramagnetic Resonance ◽  
Spin Lattice ◽  
Electron Paramagnetic

Host Spin-Lattice Relaxation Narrowing in Pr2Co3(NO3)12 · 24 H2O: Mn2+ \ Gd3+ Single Crystals

1980 ◽  
Vol 35 (12) ◽  
pp. 1308-1312 ◽  
Author(s):  
Vimal Kumar Jain
Keyword(s):  
Single Crystals ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Single Type ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Spin Lattice ◽  
X Band ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

Abstract Electron paramagnetic resonance of Mn2+ and Gd3+ in single crystals of Pr2Co3(NO3)12 · 24 H2O has been studied at X-band at 305 and 77 K. Mn2+ substitutes at two types of Co2+ sites whereas Gd3 substitutes at the single type of Pr3+ site in the lattice. The spin-Hamiltonian parameters have been evaluated. Observation of resolved Mn2+ and Gd3+ spectra at 305 K and their broadening on lowering the temperature are discussed in terms of host spin-lattice relaxation narrowing.

The detection of phase transitions in NH4Sm(SO4)2∙4H2O single crystals using the electron paramagnetic resonance of Gd3+ impurity ions

1981 ◽  
Vol 59 (4) ◽  
pp. 596-604 ◽  
Author(s):  
H. A. Buckmaster ◽  
V. M. Malhotra ◽  
H. D. Bist
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystals ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Orthorhombic Symmetry ◽  
Paramagnetic Resonance ◽  
Spin Lattice ◽  
Impurity Ions ◽  
Impurity Ion ◽  
Electron Paramagnetic

The 9.4 GHz electron paramagnetic resonance (epr) of Gd3+ impurity ions in NH4Sm(SO4)2∙4H2O single crystals has been studied at 101–297 K. The 294 K epr spectra show that the Gd3+ impurity ion substitutes for the Sm3+ host ion in two magnetically nonequivalent complexes corresponding to the tetramolecular unit cell. These spectra were analyzed using an orthorhombic symmetry spin-Hamiltonian. The observation of resolved Gd3+ impurity ion spectra in the presence of paramagnetic Sm3+ ions has been interpreted in terms of a random modulation of the interaction between the Gd3+ impurity and Sm3+ host ions by rapid spin–lattice relaxation of the Sm3+ ions. The spin–lattice relaxation time of the Sm3+ ions has been estimated at 294 K from the impurity ion epr linewidths and is found to be consistent with an Orbach resonance process. The value for τ1, has also been computed for Nd3+ ions in NH4Nd(SO4)2∙4H2O from the epr linewidth data in the literature. It has been shown for the first time that NH4Sm(SO4)2∙4H2O single crystals have the phase transition sequence[Formula: see text]

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