High-pressure dielectric behavior of polycrystalline CaMoO4: The role of grain boundaries

Application of impedance spectroscopy in exploring electrical properties of dielectric materials under high pressure

“…Alkaline molybdate materials with the chemical formula of AMoO 4 (A = Ba, Ca, Sr) are possible candidates for microwave dielectric devices due to their low dielectric constant and high-quality factor [86,87]. In-situ impedance measurements were employed to investigate the dielectric property of AMoO 4 under pressure [88][89][90]. Although the pressure-induced phase transition paths of the three compounds are similar (from tetragonal to monoclinic) [91][92][93], there are still some differences in their electrical transport and dielectric properties under pressure.…”

Improved Dielectric Properties and Grain Boundary Effect of Phenanthrene Under High Pressure

“…The imaginary part M″ as a function of frequency was shown in Figure 7C. Two peaks in the M″-f plots indicated two types of electrical response mechanisms existing in phenanthrene that represent change from long-range to shortrange carrier mobility with increasing frequency [17].…”

“…For example, Li et al [16] have reported the grain boundary effect on the electrical transport properties of β-boron at high pressure. Qin et al [17] have investigated the dielectric behavior of polycrystalline CaMoO 4 , and they found that the grain boundaries played a key role in carrier transport process. Zhang et al [18] have studied the correlation between structural phase transition and electrical transport properties of ZnFe 2 O 4 nanoparticles under high pressure, which concluded that the grain boundary effect was related to the capacity of the charge bounding.…”

Effect of High Pressure on the Dielectric Properties of SrMoO4

“…Finally, it is necessary to compare the results of SrMoO 4 with CaMoO 4 and BaMoO 4 , which has different metal cations (the radius of Ca 2+ , Sr 2+ , and Ba 2+ are 1.12, 1.26 and 1.42 Å, respectively). , On the one hand, the contribution of the grain and grain boundary to the electrical transport is different. For CaMoO 4 , the grain boundaries dominant the electronic transport process, which is reconstructed under compression.…”

“…High pressure as a powerful thermodynamic variable is an important tool to discover new structures and properties of materials. , Pressure-induced phase transition directly affects the dielectric properties of materials. − The interaction between ions, distribution of bound charge, polarization, and relaxation of these ions under external electric field are fundamental issues of structures. The systematic research on dielectric properties under high pressure will be beneficial for optimizing the performance and exploring the potential application of materials.…”