Search

Among metal disilicide materials, α‐MoSi2 exhibits high thermal conductivity and high oxidation resistance at high temperatures, making it an attractive option for high temperature applications. In the present study, we fabricate α‐MoSi2 pellets with a density of 96% theoretical density (TD) and quantify the thermal properties (thermal conductivity and thermal expansion heat capacity), mechanical properties (Vickers hardness and fracture toughness), and electrical properties (Seebeck coefficient and electrical resistivity). In this paper, we evaluate the experimental data, and present a review of the literature. In addition, we attempt to correlate the heat capacity measurement obtained experimentally with the results of our theoretical calculations to identify their relationship. [ABSTRACT FROM AUTHOR]

In this paper, temperature-dependent cathodoluminescence (CL) spectra of Er-implanted GaN thin films were measured. The effects of accelerating voltage and temperature on the CL spectra of Er-implanted GaN were investigated. In the near band-edge emission region, the competition mechanism between DAP and D0X was disclosed. A slight blue shift of the DAP emission peak with the increase of accelerating voltage was observed. The temperature dependence of the CL intensity of FX emission reveals a binding energy of ∼32 meV in Er-implanted GaN. Below 182 K, the 2H11/2 state of Er3+ is not thermally populated and the yellow band luminescence (YL) related to the defects was observed. At higher temperature, the thermal coupling between the two excited state levels of 2H11/2 and 4S3/2 of Er3+ is obvious and the YL is nearly invisible. Even at 373 K, a strong green emission at 537 nm can be observed, which indicates the Er-doped GaN is promising to be applied in high-temperature environments. [ABSTRACT FROM AUTHOR]

In this paper, the results of dielectric investigations on four different solid solutions of PbMg1/3Nb2/3O3‐PbSc1/2Nb1/2O3‐PbZn1/3Nb2/3O3 (PMN‐PSN‐PZN) are presented in a wide temperature range (from room temperature to 1100 K). At higher temperatures (above 600 K) and low frequencies, the electrical conductivity dominates in properties of these ceramics and the Maxwell–Wagner relaxation appears. The DC conductivity has some change in slope close to the Burns temperature. The value of conductivity activation energy is typical for oxygen vacancies conductivity. Close to the Burns temperature, anomalous behavior of the intrinsic dielectric permittivity is also observed due to the appearance of dielectric relaxation in the terahertz frequency range caused partially by dynamics of polar nanoregions and mainly by overdamped optical soft mode which softens toward T*. [ABSTRACT FROM AUTHOR]