Size induced tuning of dielectric behavior in nanostructured Y0.95Ca0.05MnO3 compounds

Abstract

Size is the key factor of nanostructured materials, since all the structural, transport, electrical, magnetic and other physical properties can be tuned by this factor of materials. Only the condition is to choose appropriate inexpensive scale-processing method for material synthesis which offers good control over the stoichiometry, morphology and particle size distribution. Present communication deals with the studies on the sol-gel grown Y 0.95 Ca 0.05 MnO 3 (YCMO) nanostructured compounds for their size-induced tuning of dielectric behavior. Structural studies reveal the single phasic nature with improved crystallite size with sintering temperature. Dielectric constant (real and imaginary) is found to increase with temperature and crystallite size/sintering temperature. High dielectric loss has been observed in the present system. Size dependent activation energy (E a ), obtained from modulus measurement, showing the increase in E a with crystallite size. The variation in various dielectric parameters and E a has been discussed in the light of crystallite size, crystallite boundaries, oxygen vacancies and charge carrier hopping.

Structural, optical, and dielectric characteristics of pulsed laser deposited SnO2-TiO2 composite thin films

“…As seen in figure 7(a), the dielectric constant decreases with frequency until it becomes practically frequency independent in the high-frequency zone. These results can also be expressed as follows: at lower frequencies, the dipole has enough time to align in the field direction, resulting in a higher dielectric constant value; at higher frequencies, the dipole does not have enough time to organise in the field direction, resulting in a lower dielectric constant value [42]. Ionic, dipolar, electronic, and space charge polarisation (SCP) are all known to yield the net polarisation of thin films [43].…”