(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the...(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the co-precipitation method.Using the synthesized nano-powders as initial material,Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics were fabri-cated by vacuum pre-sintering at different temperatures for 2 h and hot isostatic pressing(HIP)at 1750℃for 3 h in ar-gon.The influence of pre-sintering temperature on the microstructure,optical and luminescence properties was investi-gated.The Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics pre-sintered at 1625℃for 2 h combined with HIP post-treatment show the high-est in-line transmittance of 75.2%at 611 nm.The photoluminescence(PL)and X-ray excited luminescence(XEL)spectra of the Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)transparent ceramics demonstrate a strong red emission peak at 611 nm due to the^(5)D_(0)→^(7)F_(2) transition of Eu^(3+).The PL,PLE and XEL intensities of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics show a trend of first ascending and then descending with the increase of pre-sintering temperature.The thermally stimulated lumines-cence(TSL)curve of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics presents one high peak at 178 K and two peaks with lower intensities at 253 K and 320 K.The peak at 320 K may be related to oxygen vacancies,and the lumines-cence peak at 178 K is related to defects caused by the valence state changes of Eu^(3+)ions.展开更多
The preparation of materials with enhanced magnetocaloric properties is crucial for magnetic refrigeration. In thisstudy, Nd-doped Gd5Si4 microparticles and nanomaterials were synthesized using the reduction–diffusio...The preparation of materials with enhanced magnetocaloric properties is crucial for magnetic refrigeration. In thisstudy, Nd-doped Gd5Si4 microparticles and nanomaterials were synthesized using the reduction–diffusion method. Theimpact of Nd doping with varying compositions on the structure and entropy change properties of the materials was investigated.The Curie temperatures of both the micron- and nano-sized materials ranged from 190 K to 210 K, which were lowerthan previously reported values. Micron-sized samples doped with 1% Nd exhibited superior magnetocaloric properties,demonstrating a maximum entropy change of 4.98 J·kg^(-1)·K^(-1) at 5 T, with an entropy change exceeding 4 J·kg^(-1)·K^(-1)over a wide temperature range of approximately 70 K. Conversely, the nanomaterials had broader entropy change peaks butlower values. All samples exhibited a second-order phase transition, as confirmed by the Arrott plots.展开更多
In this manuscript, we are reporting structural, bonding, optical, dielectric, and electrical properties of Gd-doped ZnO composite samples (Zn<sub>1</sub><sub>−</sub><sub>x</sub>Gd&...In this manuscript, we are reporting structural, bonding, optical, dielectric, and electrical properties of Gd-doped ZnO composite samples (Zn<sub>1</sub><sub>−</sub><sub>x</sub>Gd<sub>x</sub>O, x = 0, 0.05, 0.10) prepared by solid-state reaction method. XRD spectra confirm the wurtzite hexagonal phase with a grain size distribution of 42 - 47 nm. The FT-IR spectra confirm bonding behavior like Zn-O, O=C=O, and O-H stretching modes. FESEM micrographs show that the grains of crystallites possess nearly spherical morphology. Optical absorption spectra confirm that the optical band gap decreases systematically from 3.19 eV to 3.15 eV for x = 0.0 to x = 0.10 samples. For all samples, PL spectra exhibited near-band emission, blue emission, and green emission peaks. The dielectric constant decreases as the applied frequency increases. Hall effect results show that with increasing doping concentration of Gd, mobility and resistivity increase while bulk concentration decreases. Current-Voltage study shows that current increases when temperature is increased. Rare earth-doped ZnO is potential material used for optoelectronics and spintronics device applications. Properties of Gd-doped ZnO are studied by various research groups, but dielectric studies are limitedly reported. Therefore, the present research work aims to study the change of electrical, optical, and dielectric properties of Gd-doped ZnO for device applications.展开更多
文摘(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the co-precipitation method.Using the synthesized nano-powders as initial material,Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics were fabri-cated by vacuum pre-sintering at different temperatures for 2 h and hot isostatic pressing(HIP)at 1750℃for 3 h in ar-gon.The influence of pre-sintering temperature on the microstructure,optical and luminescence properties was investi-gated.The Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics pre-sintered at 1625℃for 2 h combined with HIP post-treatment show the high-est in-line transmittance of 75.2%at 611 nm.The photoluminescence(PL)and X-ray excited luminescence(XEL)spectra of the Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)transparent ceramics demonstrate a strong red emission peak at 611 nm due to the^(5)D_(0)→^(7)F_(2) transition of Eu^(3+).The PL,PLE and XEL intensities of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics show a trend of first ascending and then descending with the increase of pre-sintering temperature.The thermally stimulated lumines-cence(TSL)curve of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics presents one high peak at 178 K and two peaks with lower intensities at 253 K and 320 K.The peak at 320 K may be related to oxygen vacancies,and the lumines-cence peak at 178 K is related to defects caused by the valence state changes of Eu^(3+)ions.
基金Project supported by the Natural Science Foundation of Gansu Province(Grant No.22JR5RA404).
文摘The preparation of materials with enhanced magnetocaloric properties is crucial for magnetic refrigeration. In thisstudy, Nd-doped Gd5Si4 microparticles and nanomaterials were synthesized using the reduction–diffusion method. Theimpact of Nd doping with varying compositions on the structure and entropy change properties of the materials was investigated.The Curie temperatures of both the micron- and nano-sized materials ranged from 190 K to 210 K, which were lowerthan previously reported values. Micron-sized samples doped with 1% Nd exhibited superior magnetocaloric properties,demonstrating a maximum entropy change of 4.98 J·kg^(-1)·K^(-1) at 5 T, with an entropy change exceeding 4 J·kg^(-1)·K^(-1)over a wide temperature range of approximately 70 K. Conversely, the nanomaterials had broader entropy change peaks butlower values. All samples exhibited a second-order phase transition, as confirmed by the Arrott plots.
文摘In this manuscript, we are reporting structural, bonding, optical, dielectric, and electrical properties of Gd-doped ZnO composite samples (Zn<sub>1</sub><sub>−</sub><sub>x</sub>Gd<sub>x</sub>O, x = 0, 0.05, 0.10) prepared by solid-state reaction method. XRD spectra confirm the wurtzite hexagonal phase with a grain size distribution of 42 - 47 nm. The FT-IR spectra confirm bonding behavior like Zn-O, O=C=O, and O-H stretching modes. FESEM micrographs show that the grains of crystallites possess nearly spherical morphology. Optical absorption spectra confirm that the optical band gap decreases systematically from 3.19 eV to 3.15 eV for x = 0.0 to x = 0.10 samples. For all samples, PL spectra exhibited near-band emission, blue emission, and green emission peaks. The dielectric constant decreases as the applied frequency increases. Hall effect results show that with increasing doping concentration of Gd, mobility and resistivity increase while bulk concentration decreases. Current-Voltage study shows that current increases when temperature is increased. Rare earth-doped ZnO is potential material used for optoelectronics and spintronics device applications. Properties of Gd-doped ZnO are studied by various research groups, but dielectric studies are limitedly reported. Therefore, the present research work aims to study the change of electrical, optical, and dielectric properties of Gd-doped ZnO for device applications.
