Structural and Dielectric Properties of Mg(1-x)CaxTiO3 (x=0.7, 0.8) Ceramic Materials

International audienceCalcium Magnesium titanate ceramic materials with the molar formula Mg(1-x)CaxTiO3 in which the x varies from 0.7 to 0.8 were synthesized by conventional Solid State Reaction method. The XRD pattern revealed that the samples exhibit Orthorhombic structure. The microstructure and surface morphology for the samples was studied by SEM. The elemental composition was studied by EDAX. The dielectric response of both samples was measured by HIOKI 3532-50 LCR HiTESTER in the frequency range of 1KHz-1MHz from room temperature to 350 0 C. These samples find applications in capacitors, microwave antennas, stainless steel electrodes and data storage devices. Introduction. Over more than 200 years, Ceramic materials are known for technical applications. To overcome the limitations of other conventional materials, various special tailored ceramics are developed with novel chemical, electrical, biological and mechanical properties. In the last three decades there has been a phenomenal transformation in microwave communication systems such as mobile telecommunication systems, satellite communication and broadcasting systems, and global positioning systems. The rapid development in microwave communication systems was made possible with the use of dielectric ceramics as enabling materials for resonators, filters and other key components in microwave components. For these applications the ceramic materials are required to have a high relative permittivity (εr), low dielectric loss, and near zero temperature coefficient of resonant frequency (τf). The combination of these requirements greatly restricts the ceramic dielectrics available for applications in microwave systems [1]

Surface modification influenced properties of silicon nanowires grown by Ag assisted chemical etching with ECR hydrogen plasma treatment

Silicon nanowires (SiNWs) are fabricated by Ag assisted chemical etching and are treated with hydrogen plasma created by electron cyclotron resonance (ECR) plasma system at 600 watts microwave power for various time durations (0�30 min). The hydrogen plasma exposure on the surface of the SiNWs reduced the surface roughness and increased the crystalline nature. SEM analysis revealed that the diameter of the SiNWs decreased on plasma exposure. The electrical conduction measurements suggested that the hydrogen plasma exposure for 5 min on the SiNW surface enhanced the electrical conductivity when compared to as fabricated SiNW surface. The hydrophobic nature of fabricated SiNWs was transformed to hydrophilic at plasma exposure for lower time duration. On plasma exposure of NWs for 30 min the sample turned hydrophobic. Study of different properties of the SiNWs before and after plasma treatment revealed that there is pronounced effect of plasma on the nature of SiNWs