Summerfield scaling model and electrical conductivity study for understanding transport mechanisms of a Cr³⁺ substituted ZnAl₂O₄ ceramic

Abstract

We have adopted two methods, sol–gel and solid-state synthesis methods to show the effect of grain size and the effect of temperature in the conductivity study.

Near‐Infrared I/II Nanophosphors with Cr3+/Ni2+ Energy Transfer for Bioimaging

“…The signals which are close to free electron value ( g = 2.0023) are generally attributed to an unpaired electron trapped on an oxygen vacancy site. On the other hand, in the case of ZnAl 1.95 Cr 0.05 O 4 , [ 32 ] chromium doping leads to the following substitution: half of the octahedral sites and one eighth of the tetrahedral sites are full. Thus, chromium can substitute either Zn 2+ or Al 3+ positions in this spinel.…”

Comprehensive characterization and optoelectronic significance of Ho3+ and Cr3+ Co-doped ZnAl2O4 spinels

“…The spinel family, characterized by the general formula AB 2 O 4 , plays a pivotal role in the realm of oxide materials, showcasing exceptional physical properties that have garnered significant attention. [1][2][3][4][5][6][7][8][9][10][11] This intriguing composition involves a metal cation (A) occupying a tetrahedral (Td) site, typically represented by elements such as Zn 2+ or Mg 2+ , while a cation (B) fills an octahedral (Oh) site, commonly represented by elements such as Al 3+ or Ga 3+ .…”

“…The B-site of spinels accommodates various luminescent activators, including ions of transition metals (TM) or lanthanides (Ln), resulting in a broad spectrum of spinels with captivating luminescence properties. 5,6,11 This unique characteristic opens up a myriad of possibilities in the field of optoelectronics, where the combination of optical and structural properties makes spinels highly desirable.…”

“…Recently, studies have been performed on the structural, electrical, vibrational, and optical characteristics of a novel spinel persistent phosphor of ZnAl 0.095 Cr 0.05 O 4 prepared by solid-state and sol-gel techniques. 5,6,11 The interpretation of the ambient temperature Raman and infrared (ATR-IR) spectra has been completed. The direct transition behavior has been confirmed using Tauc's law, and the optical band gap E g has been determined from absorption UV/ vis spectra.…”

“…The electronic structure of Cr 3+ , with a 3d 3 electronic configuration, was determined via a crystal field analysis in the O h symmetry site using the absorption and photoluminescence excitation (PLE) spectra. 5,6,11 In this study, ZnAl 1.99−x Ho x Cr 0.01 O 4 (with x = 0 and 0.001) spinels were synthesized through solid-state reaction and subsequently characterized using structural and optical techniques. The Ho 3+ ion, belonging to the lanthanide family with an electron configuration of 4f 10 , was incorporated into the spinel lattice.…”