The magneto‐optical ceramics of terbium oxide doped with different rare earth elements (REE) REE:Tb2O3 (REE—Y3+, Lu3+, Sc3+, Ce3+, Dy3+, Ho3+, Yb3+, Nd3+) are successfully fabricated by hot pressing ...using powders obtained by the self‐propagating high‐temperature synthesis (SHS) method. The prepared REE:Tb2O3 ceramics have good optical quality and magneto‐optical properties. The in‐line transmittance of Tb2O3 ceramics doped with REE except Sc3+ is close to undoped terbium oxide, especially in the long‐wavelength region. The Verdet constant of the REE:Tb2O3 samples considered at 633 nm is about 3.3 and 2.6 times higher in absolute value than that of the commercial terbium–gallium garnet (TGG) single crystal and terbium–aluminum garnet (TAG) ceramics, respectively. It is noted that REE (except Yb3+ and Nd3+) doping only slightly increases the Verdet constant of pure Tb2O3 (when the content of terbium ions in the optical element is taken into consideration in the calculation). The dilution of the Tb2O3 matrix with REE in relatively high concentrations leads to a decrease in the absolute value of the Verdet constant.
Rare earth elements in terbium oxide ceramics increase its Verdet constant, normalized to the concentration of terbium ions. However, the Verdet constant absolute value decreases due to the dilution of the Tb2O3 matrix with rare earth elements. Thus, pure terbium oxide has a record Verdet value among the studied materials.
A cycle of works on manufacturing and studying laser and magnetooptical ceramics with a focus on their thermo-optical characteristics performed by the research team is analyzed. Original results that ...have not been published before such as measurements of the Verdet constant in the Zr:TAG, Re:MgAl2O4, and ZnAl2O4 ceramics are also presented.
The synthesis of nanopowders of terbia compounds with scandia, yttria, and lutetia was carried out using a self-propagating high-temperature synthesis method involving a mixture of nitrates of metals ...and glycine as a precursor. The nanopowder phase transformations were investigated using X-ray diffraction analysis. It was found that lutetia has a negligible effect on the phase formation in terbia. On the other hand, yttrium and scandium ions significantly suppressed crystallization. The densification kinetics of nanopowders of the Tb
2
O
3
compounds and the microstructure of ceramics after microwave sintering were studied using dilatometry and scanning electron microscopy. The introduction of scandia, yttria, or lutetia contributed to the intensification of the densification of the terbia ceramics when heated in a microwave field. Near full-density materials of terbia solid solutions with lutetia and yttria were obtained at about 1600–1640 °C. The ceramics of scandia–terbia compounds contained the second phase, which causes light scattering.
A glycine-nitrate self-propagating high-temperature synthesis (SHS) was developed to produce composite MgO-Gd
2
O
3
nanopowders. The X-ray powder diffraction (XRD) analysis confirmed the SHS-product ...consists of cubic MgO and Gd
2
O
3
phases with nanometer crystallite size and retains this structure after annealing at temperatures up to 1200 °C. Near full dense high IR-transparent composite ceramics were fabricated by spark plasma sintering (SPS) at 1140 °C and 60 MPa. The in-line transmittance of 1 mm thick MgO-Gd
2
O
3
ceramics exceeded 70% in the range of 4–5 mm and reached a maximum of 77% at a wavelength of 5.3 mm. The measured microhardness HV0.5 of the MgO-Gd
2
O
3
ceramics is 9.5±0.4 GPa, while the fracture toughness (
K
IC
) amounted to 2.0±0.5 MPa·m
1/2
. These characteristics demonstrate that obtained composite MgO-Gd
2
O
3
ceramic is a promising material for protective infra-red (IR) windows.
Transparent ceramics based on ytterbium oxide have been successfully produced by vacuum sintering of self-propagating high-temperature synthesized powders with use of a La2O3 sintering aid. Phase ...composition and microstructure of the initial powders were studied by X-ray diffraction analysis and scanning electron microscopy. It was found that addition of 5 mol.% of La2O3 does not cause formation of secondary phases in the Yb2O3 powders. The 4% La:Yb2O3 ceramics showed the best in-line transmittance of 73% at a wavelength of 2 μm among the studied samples. Dependence of the Verdet constant on wavelength was investigated in the range of 0.4–2 μm. The most promising finding is use of the obtained material as Faraday isolators in the wavelength region of ~1.5 μm, where there are no absorption bands, and the Verdet constant is 8.6 rad/(T*m).
Glycine-nitrate self-propagating high-temperature synthesis was used to synthesize terbium oxide nanopowders whose phase transformations were investigated by methods of high-temperature differential ...scanning calorimetry, dilatometry, and X-ray diffraction analysis. The as-prepared powders consisting of Tb7O12 and Tb11O20 phases were converted to Tb2O3 after calcination at 600–800°C in reducing atmosphere. The sintering behavior of Tb2O3 was studied under microwave heating up to 1780°C. The microstructure of the powders and ceramics was investigated by scanning electron microscopy. Near full-density material was obtained at about 1620°C. Further temperature increases causes a deterioration of the ceramics microstructure due to monoclinic Tb2O3 phase formation.
The magneto‐optical ceramics of terbium oxide doped with different rare earth elements (REE) REE:Tb
2
O
3
(REE—Y
3+
, Lu
3+
, Sc
3+
, Ce
3+
, Dy
3+
, Ho
3+
, Yb
3+
, Nd
3+
) are successfully ...fabricated by hot pressing using powders obtained by the self‐propagating high‐temperature synthesis (SHS) method. The prepared REE:Tb
2
O
3
ceramics have good optical quality and magneto‐optical properties. The in‐line transmittance of Tb
2
O
3
ceramics doped with REE except Sc
3+
is close to undoped terbium oxide, especially in the long‐wavelength region. The Verdet constant of the REE:Tb
2
O
3
samples considered at 633 nm is about 3.3 and 2.6 times higher in absolute value than that of the commercial terbium–gallium garnet (TGG) single crystal and terbium–aluminum garnet (TAG) ceramics, respectively. It is noted that REE (except Yb
3+
and Nd
3+
) doping only slightly increases the Verdet constant of pure Tb
2
O
3
(when the content of terbium ions in the optical element is taken into consideration in the calculation). The dilution of the Tb
2
O
3
matrix with REE in relatively high concentrations leads to a decrease in the absolute value of the Verdet constant.
A glycine-nitrate self-propagating high-temperature synthesis (SHS) was developed to produce composite MgO-Gd.sub.2O.sub.3 nanopowders. The X-ray powder diffraction (XRD) analysis confirmed the ...SHS-product consists of cubic MgO and Gd.sub.2O.sub.3 phases with nanometer crystallite size and retains this structure after annealing at temperatures up to 1200 degreesC. Near full dense high IR-transparent composite ceramics were fabricated by spark plasma sintering (SPS) at 1140 C and 60 MPa. The in-line transmittance of 1 mm thick MgO-Gd.sub.2O.sub.3 ceramics exceeded 70% in the range of 4-5 mm and reached a maximum of 77% at a wavelength of 5.3 mm. The measured microhardness HV0.5 of the MgO-Gd.sub.2O.sub.3 ceramics is 9.5 + or - 0.4 GPa, while the fracture toughness (K.sub.IC) amounted to 2.0 + or - 0.5 MPa*m.sup.1/2. These characteristics demonstrate that obtained composite MgO-Gd.sub.2O.sub.3 ceramic is a promising material for protective infra-red (IR) windows. Keywords: MgO-Gd.sub.2O.sub.3; self-propagating high-temperature synthesis (SHS); spark plasma sintering (SPS); optical properties; infra-red (IR) ceramics
The temperature dependences of a Verdet constant of ceramic samples with the compositions (DyxY0.95−xLa0.05)2O3, x = 0.7, 0.85, 0.9 and their approximations in the temperature range 80–294 K and in ...the wavelength range 405–1064 nm were obtained with the <10% deviation from the experimental data. Cryogenic cooling leads to increase the Verdet constant value, proportional to inverse temperature, which allows to shorten a magneto–optical element length in cryogenic Faraday isolators. Results obtained are necessary for developing of Faraday devices for Tm3+ and Ho3+ lasers, and for lasers operating in the visible spectral region.
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The method of self-propagating high-temperature synthesis of submicron powders with subsequent vacuum sintering was used to produce erbium oxide-based ceramics with the compositions ...(Er0.93La0.07)2O3, (Er0.95La0.05)2O3, (Er0.97La0.03)2O3, and Er2O3. The studied material has transmission windows near the wavelengths of 427 nm and 467 nm and in the 565–626 nm, 685–780 nm, 851–920 nm, 1030–1370 nm, and 1800–8000 nm wavelength regions. The wavelength dependence of the Verdet constant in the region of 400–1100 nm was measured at room temperature, and its approximation was obtained with allowance for the influence of the absorption lines on the Verdet constant.
•Erbium oxide based ceramics was prepared with the use of La2O3 sintering additive.•The transmission of erbium oxide ceramics was measured in the range 0.2–11 μm.•The Verdet constant in the region 0.4–1.1 μm was measured for the first time.•The main electron transitions influence on the Verdet constant behavior is compared.
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