Role of Extrinsic Doping of Mg2+ on Crystallographic and Morphological Transition in CdO Nanoparticles under Acoustic Shocked Conditions

The role of extrinsic dopants in acoustic shock wave-induced phase transitions of solids remains unclear. Herein, we report the crystallographic structural stability of the Mg-doped CdO nanoparticles under acoustic shocked conditions to understand how extrinsic doping of Mg2+ manipulates the critical pressure for the B1–B2 transition compared to pure CdO NPs. From the XRD results, Mg-CdO remains stable in the B1 phase at 200 shocks, whereas the B1–B2 transition occurs in pure CdO at 200 shocks. Even in the absence of structural transitions, sphere-to-hexagonal honeycomb morphological changes are observed, which bring some considerable modifications in the vibrational, optical, and magnetic properties of the Mg-CdO NPs. The values of optical band gap energy are determined as 2.30, 2.23, and 2.22 eV for 0, 100, and 200 shocks, respectively, and the saturation magnetization values are found to be 0.14, 0.33, and 0.14 emu/g for 0, 100, and 200 shocks, respectively. The observed findings demonstrate that the presence of Mg2+ enhances the critical pressure for the B1–B2 transition compared to pure CdO. Moreover, the observed morphological changes are discussed based on the shock wave-induced thermal conductivity-driven superheating concepts.