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D.P. Rojas L. Fernández Barquín C. Echevarria-Bonet J. Rodríguez Fernández 《Solid State Communications》2012,152(19):1834-1837
Measurements of the magnetization and specific heat of YbNi2 binary alloy are reported. The DC magnetic susceptibility displays a ferromagnetic behavior with a Curie temperature TC=10.5 K, one of the highest found in Yb compounds. Moreover, the temperature dependence of the specific heat exhibits a lambda anomaly with a peak of 5.12 J/mol K at 9.4 K. The analysis also shows an additional magnetic contribution around 32 K stemming from the crystalline electric field of a quartet at and a doublet at , according to the splitting of the Yb3+ ion in cubic symmetry. From the magnetic contribution to the specific heat, a relatively high Kondo temperature is estimated. Below the magnetic transition, the specific heat shows a huge value of the electronic coefficient , which is a signature of a heavy fermion behavior. Therefore, this alloy is a fine example of enhanced ferromagnetism and heavy fermion behavior among Yb compounds. 相似文献
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《Journal of Physics and Chemistry of Solids》2007,68(5-6):725-728
Metal//a-Si-/c-Si structures containing amorphous silicon nanoparticles (a-Si NPs) embedded in ultra thin matrix are fabricated by thermal evaporation of and sputtering of layers followed by thermal annealing at . A memory effect, due to charging of a-Si NPs in , is observed. The processes of NP charging and discharging are accomplished by applying pulses with alternative polarities. The observed shift of the flat band voltage of the high-frequency C–V curve caused by a voltage pulse of having duration of 1 s is more than 3 V. In addition, the structures show good retention characteristics which make them promising for application in non-volatile memory devices. 相似文献
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《Radiation measurements》2007,42(4-5):807-810
Thermally stimulated luminescence (TSL) was studied for many crystals after their selective irradiation at 80–220 K in the 3.4–5.0 eV energy range to clarify the origin of the defects responsible for the TSL peaks located in the 200–250 K range. The conclusion is made that both in and : crystals the total TSL intensity and the intensity ratio of various TSL peaks are mainly determined by the concentration and type of oxygen and lead vacancies which depend on the crystal preparation and annealing conditions and on the concentration of trivalent rare-earth impurity ions. The TSL peak near 200 K is ascribed to centers and the peak in the 210–230 K range, to the electron centers, containing oxygen vacancies of the type of and WO. Only the 250 K peak arises from electron centers. Thermally stimulated processes are accompanied with the green G(II) emission. 相似文献
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《Radiation measurements》2007,42(4-5):719-722
Luminescence and luminescence excitation under VUV radiation of (, K, Cs; , In) double phosphates are studied. Two emission bands peaking near 330 and 420 nm are common for investigated crystals. The band structure and partial densities of electronic states of perfect , and crystals are calculated by the full-potential linear-augmented-plane-wave (FLAPW) method. It is found that the structures of the conduction bands of crystals, which have different B cations, are appreciably different. Experimental results are compared with results of calculations of the electronic structure. Assumptions concerning the origin of luminescence in double phosphates are made. 相似文献
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《Radiation measurements》2007,42(4-5):665-667
The synthesized :Cu particles were characterized using X-ray diffraction (XRD) to determine the nanocrystallite size and crystal structure, respectively. The :Cu powder with a crystallite size of 30–40 nm has a monoclinic structure and exhibit a thermoluminescent (TL) glow curve with two peaks centered at 130 and . The TL response of :Cu as a function of wavelength exhibited two maxima at 260 and 290 nm. The TL response of :Cu as a function of the UV light spectral irradiance was linear in the range from 10 to . Fading and reusability of the phosphor were also studied. The results showed that :Cu nanopowder has potential to be used as a UV dosimeter in UV radiation monitoring. 相似文献
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《Radiation measurements》2007,42(4-5):869-873
The spectral-luminescent studies of the single crystals are reported. The fast luminescence in the 3.6–2.0 eV energy range with decay time was revealed in the crystal under high-energy excitation at 9 K. This luminescence is supposed to be caused by the hole transitions between subbands of the split valence band. The energy-band picture for crystals was calculated as a proof of the luminescence model. 相似文献
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