|
NISCAIR ONLINE PERIODICALS REPOSITORY (NOPR) >
NISCAIR PUBLICATIONS >
Research Journals >
Indian Journal of Engineering and Materials Sciences (IJEMS) >
IJEMS Vol.15 [2008] >
IJEMS Vol.15(2) [April 2008] >
| Title: | Electrical properties of ferromagnetic Ag:CrO₂ particles |
| Authors: | Singh, G P
Ram, S
Thakur, A K
Choudhary, R N P |
| Issue Date: | Apr-2008 |
| Publisher: | CSIR |
| Abstract: | A stable silver modified CrO₂, i.e., Ag:CrO₂ of nanocomposite particles was synthesized with a novel chemical method involving Cr⁶⁺, Ag⁺ and NO₃⁻ species in an aqueous solution. A single phase Ag:CrO₂ of submicron size particles (~33 nm average crystallite size) of a Pnnm orthorhombic structure (lattice parameters a = 0.4405 nm, b = 0.4452 nm and c = 0.2885 nm) is obtained after annealing at 573 K in air. Microstructure reveals single domain Ag:CrO₂ particles of prismatic shapes (aspect ratio L/b ~ 1-2) of average b ~30 nm width and 40 to 50 nm length (L). The temperature dependence electrical resistance R (T) shows a phase transition from a metallic to a semiconductor like at a specific temperature TC , which is found to be 405 K at a frequency f = 1 kHz. At 10 kHz, the dielectric constant Ɛr has as large a value as 49, with power loss 0.42. As a function of increasing the f-value, both εr and power loss have been shown to decrease monotonically to the values 28 and 0.06 respectively. The εr gets saturated at f ≥ 400 kHz. |
| Page(s): | 171-175 |
| ISSN: | 0971-4588 |
| Source: | IJEMS Vol.15(2) [April 2008]
|
|
