Аннотация:: Iron-containing oxides are the most important functional substance class and find a tremendous variety of applications. An attractive modern application is their use in biomedical technologiesas components in systems for imaging, drug delivery, magnetically mediated hyperthermia, etc. Inthis paper, we report the results of the experimental investigation of submicron Y3Fe5O12 garnetparticles obtained in different sizes by solution combustion synthesis (SCS) using glycine organicfuel to discuss the interdependence of peculiarities of the crystal and magnetic structure and size’sinfluence on its functional magnetothermal performance. A complex study including Mössbauer andRaman spectroscopy accompanied by X-ray diffractometry, SEM, and measurements of field andtemperature magnetic properties were performed. The influence of the size effects and perfectnessof structure on the particle set magnetization was revealed. The ranges of different mechanisms ofmagnetothermal effect in the AC magnetic field were determined.