Adjusting the Magnetic Properties of ZrO2:Mn Nanocrystals by Changing Hydrothermal Synthesis Conditions

The aim of the present work was to study the magnetic properties of ZrO2(Mn) nanocrystals prepared by microwave-assisted hydrothermal synthesis using three different precursors: KMnO4, MnCl2, and Mn(NO3)(2). The structural characterization was performed by means of X-ray diffraction. The morphology of the samples was studied by using STEM microscopy. The magnetic properties were studied by means of alternating current (AC) susceptibility (at a small AC magnetic field with amplitude not exceeding 5 Oe) and direct current (DC) magnetization (up to 9 T). All of the samples demonstrated Curie-Weiss behavior at higher temperatures with negative values of the Curie-Weiss temperature theta. It was shown that the conditions of the synthesis, e.g., pH and the type of precursor, can be adjusted to decrease the value of the Curie-Weiss temperature and reduce antiferromagnetic interactions.