Switchable phase transitions from non-magnetic to magnetic cerium oxide nanoparticles using acoustic shock waves

In the present framework, we report a reversible magnetic phase transition that occurs from a mixed diamagnetic (nonmagnetic) state to a weak ferromagnetic (magnetic) state exhibited by cerium oxide nanoparticles (CeO2 NPs) under shocked conditions wherein the magnetic phase transitions are observed to be switchable phase transitions of mixed diamagnetic - weak ferromagnetic - mixed diamagnetic - weak ferromagnetic for the respective shock pulses of 0, 50, 100 and 150, which is probably reported for the first time, and the observed values of the saturation magnetization are 0.9117, 0.1022, 0.8783 and 3.7780 emu/g, respectively. The possible reasons behind the observed reversible magnetic phase transition are proposed by the outcomes attained from the spectroscopic and microscopic techniques. Based on the obtained analytical results, it is confirmed that the observed room temperature weak ferromagnetism is because of the enhancement of Ce3+ ions (reduction of Ce4+ ions) and oxygen vacancies such that the title material is suggested for the applications of magnetic sensors.