Crystal growth of PbWO4:Nd3+ and PbMoO4:Nd3+ crystals and their characterization by means of optical and dielectric relaxation spectroscopy

Synthesis, structure, and thermal stability of new scheelite-type Pb1−3x□xPr2x(MoO4)1−3x(WO4)3x ceramic materials

“…The values of band gap energy for n = 2, i.e., for indirect allowed transition of an electron from a valance to a conduction band are showed in Table 1. The E g value for PbMoO 4 was found to be 3.17 eV, and this value is very close to those ones reported earlier, i.e., 3.14-3.19 eV [22] is a slightly lower and equals 3.21 eV. It was also shown a nonlinear (parabolic) variation in the band gap with x parameter (Fig.…”

“…They have been used as laser host materials, Raman lasers, optical fibers, humidity sensors, magnetic and photoluminescence materials, and catalysts [1][2][3][4][5][6][7][8][9][10][11][12][13]. Among them, lead molybdate and lead tungstate are very attractive materials because of their applications as acousto-optical modulators, deflectors, ion conductors, and solid-state scintillators for a nuclear instrumental application [14][15][16][17][18][19][20][21][22]. These materials doped with RE 3? ions exhibit good photoluminescence, and they are promising as laser hosts [14,22].…”

“…Among them, lead molybdate and lead tungstate are very attractive materials because of their applications as acousto-optical modulators, deflectors, ion conductors, and solid-state scintillators for a nuclear instrumental application [14][15][16][17][18][19][20][21][22]. These materials doped with RE 3? ions exhibit good photoluminescence, and they are promising as laser hosts [14,22]. Lead molybdate crystallizes with a scheelite-type tetragonal structure and has a space group (I4 1 /a), as well as four molecular formulas per unit cell (Z = 4) [1,11,15,19,20,23,24].…”

Peculiar Structural Effects in Pure and Doped Functional Single Crystals of Complex Compositions

“…The occurrence of La ions in the W lattice and existence of interstitial oxygen in 1.0-and 2.5-mol% PWO:La crystal samples is confirmed by the results of X-ray photoelectron spectroscopy and extended X-ray absorption fine spectroscopy measurements of W-L 3 absorption [34]. In addition to the concentration of dopant ions, a formation of point defects is also affected by the doping schemes, in particular, the initial composition of the compound containing dopant ions [33]. Refinement of PMO and PWO crystal structures were performed based on a single-crystal X-ray experiment [35] and by the Rietveld method [36], however, the occupancy factors for the crystallographic sites were not refined and site deficiency was not estimated.…”

“…In this case, charge compensation occurs due to the formation of vacancies in the Pb site. For higher doping concentrations (more than 1.5 wt% [33] and 1 mol% [32]), Nd 3+ is incorporated into the Pb 2+ and W 6+ sublattices, the excessive negative charge being compensated by oxygen vacancies [33]; La 3+ ions enter the W 6+ sublattice and charge compensation is due to the interstitial oxygen [32]. The occurrence of La ions in the W lattice and existence of interstitial oxygen in 1.0-and 2.5-mol% PWO:La crystal samples is confirmed by the results of X-ray photoelectron spectroscopy and extended X-ray absorption fine spectroscopy measurements of W-L 3 absorption [34].…”