http://localhost:8080/xmlui/handle/123456789/48 2026-01-28T11:28:18Z 2026-01-28T11:28:18Z K. Deva Arun Kumar S. Valanarasu Brian Jeevan Fernandes http://localhost:8080/xmlui/handle/123456789/1990 2022-05-25T08:33:28Z 2020-01-01T00:00:00Z

Title: Effect of Er Doping on the Ammonia Sensing Properties of Zno Thin Films Prepared by A Nebulizer Spray Technique Authors: K. Deva Arun Kumar; S. Valanarasu; Brian Jeevan Fernandes Abstract: Erbium (Er)-doped ZnO thin films were deposited on glass substrates by nebulizer spray pyrolysis with different doping concentrations (0wt%, 1 wt%, 3 wt% and 5 wt%). The deposited films are polycrystalline with a hexagonal structure with a (002) predominant plane. The Erdoped ZnO films have greater surface roughness than the undoped ZnO film. The optical transmittance of the undoped ZnO film is about 80% in the visible range. The optical bandgap of the undoped ZnO thin film is 3.29 eV, which is very close to the bulk ZnO. From photoluminescence spectra, sharp UV emission is observed at 385 nm for all the prepared films. The response of the films to ammonia (NH3) vapour is high when the Er concentration is 3% or less, and for higher concentrations of Er, the response is low. All the deposited Er-doped ZnO films show short response time and recovery time with regard to NH3.

2020-01-01T00:00:00Z K Manjunatha V Jagadeesha Angadi U Mahaboob Pasha http://localhost:8080/xmlui/handle/123456789/1988 2022-05-25T08:33:28Z 2020-01-01T00:00:00Z

Title: Exploring the Structural, Dielectric and Magnetic Properties of 5 Mol% Bi3+-Substituted CoCr2O4 Nanoparticles Authors: K Manjunatha; V Jagadeesha Angadi; U Mahaboob Pasha Abstract: In the present work for the first time, we report in-depth structural, electrical, optical and magnetic properties of a family of cobalt chromate nanoparticles with 5 mol% Bi3+ substitution of the average crystallite size of 15 nm, fabricated by a solution combustion method using urea and glucose as a fuel. Co0.95Bi0.05Cr2O4 shows a single phase with spinel cubic structure with a space group of Fd3m with a lattice parameter of 8.334 Å. The morphology of the family of Bi3+-doped CoCr2O4 shows a highly porous nature. Transmission electron microscopy (TEM) shows samples are in nano size, i.e. 22 nm with well crystalline nature. The energy gap was estimated by using UV spectrum and found in the range of 3.86 eV. Temperature-dependent dielectric constant (ε′), dielectric loss (ε″) and loss tangent (tan δ) are explained by using Maxwell–Wagner and Koop’s phenomenological theory. The evolution of magnetic behaviour was studied as a function of temperature and magnetic field to study the magnetic transitions such as paramagnetic to long-range collinear ferrimagnetism transitions, and it was found at 98 K and non-collinear ferrimagnetism at 26 K. M−H loop at 300 K nearly shows a paramagnetic phase at 98 K and it clearly suggests that samples exhibit super paramagnetic nature.

2020-01-01T00:00:00Z Biswas Tanujit G Sreevidya Varma Sundarrajan Asokan http://localhost:8080/xmlui/handle/123456789/1986 2022-05-25T08:33:28Z 2019-01-01T00:00:00Z

Title: Switching Behavior of Bulk, Fast Ion Conducting, Vitreous AgI‐Ag2O‐MoO3 Solids with Inert Electrode Authors: Biswas Tanujit; G Sreevidya Varma; Sundarrajan Asokan Abstract: Developing efficient, fast performing and thermally stable Silver iodide‐based fast ion conducting solids are of great interest for resistive switching applications, but still remain a challenge. Metallization in bulk, behavior of threshold voltage profile over composition, and corrosion reactions are few of the challenges. In this work, the switching behavior of bulk, fast ion conducting, vitreous (AgI)x ‐(Ag2O)25‐(MoO3)75‐x , for 60 ≤ x ≤ 40 solids, has been investigated in order to understand the switching mechanism with the inert electrodes. By using inert electrodes, the switching becomes irreversible, memory type. The switching mechanism is the electrochemical metallization process. The inert electrodes restrain ionic mass transfer but exhibit low barrier to electron transfer allowing the cathodic metallization reaction to reach Nernst equilibrium faster. Cations involved in this process transport through the free volume within the solid structure and follows Mott‐Gurney model for electric field‐driven thermally activated ion hopping conductivity model. This model along with the thermal stability profile provides a narrow region within composition with better switching performance based on swiftness to reach threshold voltage and less power loss. Traces of anionic contribution to metallization are absent. Moreover, anodic oxidation involves reactions that cause bubble formation and corrosion.

2019-01-01T00:00:00Z H.R.Lakshmiprasanna V.Jagadeesha Angadi B.Rajesh Babu Mehaboob Pasha K.Manjunatha http://localhost:8080/xmlui/handle/123456789/1985 2022-05-25T08:33:28Z 2019-01-01T00:00:00Z

Title: Effect of Pr3+-Doping on the Structural, Elastic and Magnetic Properties of Mn–Zn Ferrite Nanoparticles Prepared By Solution Combustion Synthesis Method Authors: H.R.Lakshmiprasanna; V.Jagadeesha Angadi; B.Rajesh Babu; Mehaboob Pasha; K.Manjunatha Abstract: Ferrite nanoparticles are currently used for important applications in the field of medical particularly, target-directed medicine and cancer treatment. Keeping this in mind, in the present work we prepared Pr3+ doped Mn0.5Zn0.5Fe2O4 nanoparticles by combustion route. The crystallinity and structure were confirmed by XRD. The Elastic properties are estimated by using FTIR data and reveals that variation of elastic constants has been interpreted in terms of strength of inter-atomic bonding and electronic configuration of the cations involved in the samples. Further variation of stiffness constants, Poison's ratio, elastic constants, longitudinal and transverse wave velocity is studied with respect to Pr3+content. Significant influence is observed in elastic values due to the addition of larger ionic radii of Pr3+ in spinel lattice. The intensity of magnetization, remanence, and coercivity was found to be decreasing with increasing Pr3+ concentration. Hence these samples are potential candidates for medical applications i.e. magnetic resonance imaging.

2019-01-01T00:00:00Z