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 θ. 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.