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Pure and metal‐doped ZnO nanopowders with composition formula M0.04Zn0.96O (where M = Al, Mg, Sm, and Cu) are synthesized using the coprecipitation method. The structural characterization of synthesized powders is investigated using X‐ray diffraction and the results confirm the hexagonal wurtzite structure without any additional phases. The change in structural parameters of ZnO with dopants is estimated using X‐ray peak profile analysis. The structural characterization is further analyzed by Fourier‐transform infrared spectroscopy. The size and morphology of the synthesized powders are analyzed by a field‐emission scanning electron microscope, which also evidences the formation of uniform nanostructures with quasi‐spherical and hexagonal shapes. Moreover, the elemental composition of these metal‐doped nanotructures is determined by energy‐dispersive X‐ray measurements. UV–vis spectroscopy is used to determine the energy bandgap of ZnO nanopowders. A vibration sample magnetometer is employed to measure the samples' magnetic properties, and dopants are found to induce distinct magnetic behaviors in ZnO. The antimicrobial activity of the synthesized powders is measured using the well diffusion method. It is observed that the introduction of dopant metals leads to increased microbial activity. Among the doped ZnO variants, Al‐doped ZnO exhibits the highest level of microbial activity compared to pure ZnO and other samples. [ABSTRACT FROM AUTHOR]

A series of polycrystalline La0.5Ca0.5Mn1−xNixO3(x = 0.00, 0.025, 0.050, 0.075, 0.100 and 0.125) was synthesised using solid state reaction. Measurements in a cooling and warming cycle between 300 and 80 K were carried out to study the Ni-doping effects on the electrical resistivity, thermopower and magnetisation of single-phase La0.5Ca0.5Mn1−xNixO3. Partial substitution of Ni for Mn leads to the suppression of charge ordering state, the evidence of which is shown by the dramatic decrease in electrical resistivity and thermal hysteresis width in electrical resistivity, thermopower and magnetisation. However, the magnitude of both electrical resistivity and thermopower increases with increasing Ni content. This can be attributed to an increase in the Mn4+concentration, which favours the antiferromagnetic state and leads to a gradual disappearance of ferromagnetic double exchange interaction. Besides, the metal–nonmetal transition temperature decreases with increasing Ni content untilx = 0.075, which might arise from increased electron–phonon coupling due to less ordered spins at temperatures above ferromagnetic transition. For samples withxgreater than 0.075, no metal–nonmetal transition is observed due to the suppression of double exchange mechanism. [ABSTRACT FROM PUBLISHER]