Study of the effect of temperature for hydrothermal synthesis on the properties of micro/nanostructured samarium garnet ferrite powders

Background. The increased interest of researchers in nanoobjects is caused by the detection of unusual physical and chemical properties in them, which is related to the demonstration of so-called “quantum dimensional effects”. A special place among them is occupied by magnetic properties, in which differences between massive (bulk) material and nanomaterials are most clearly evident. By changing the size, shape, composition and structure of the nanoparticles, it is possible to control the magnetic characteristics of the materials based on them within certain limits, which makes the presented research results undoubtedly relevant. The aim of this work is an experimental study of the effect of hydrothermal synthesis temperature on the magnetic properties of nanostructured samarium garnet ferrite powders. Materials and methods. The chemical and phase composition of synthesized samarium garnet ferrite powders was examined by X-ray phase analysis on a Bruker D8 Advance diffractometer. The experiment was conducted with a vertical copper goniometer with a wavelength of CuK$_{\alpha} = 1,54$ Å at angles $\theta/2\theta = 10^\circ - 90^\circ$. Ranges of the Raman dispersion at the room temperature registered by the Raman spectrometer of Jobin-Yvon (LabRAM ARAMIS) equipped with the CCD detector and the diode junction laser ($\lambda = 785$ nm) $35$ mW as an excitation source. The magnetic properties of the synthesized samples were examined at room temperature on a Quantum Design Physical Property Measurement System (QuantumDesign PPMS) magnetometer. Results. Nanostructured samarium garnet ferrite powders were synthesized by a light hydrothermal method at various temperatures. The dependence of magnetic characteristics on the value of external magnetic field taking into account the temperature of powder synthesis has been investigated. Comparison was made with the experimental data of other authors and good agreement with them was demonstrated. The mechanisms of magnetic activity of samarium garnet ferrite powders have been suggested. Conclusions. Change of temperature of soft hydrothermal synthesis can be successfully controlled by magnetic properties of samarium ferrites with different morphology of particles.