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Magnetite is a common mineral in soils that can be both pedogenic and lithogenic in origin. However, magnetite is unstable in environment and can undergo various changes in structure and magnetic properties, which in turn affects the magnetic properties of soils. These changes are quite diverse and depend on temperature, time, redox conditions, etc. In this work, the transformation of magnetite nanoparticles by heating under oxidizing and reducing conditions was experimentally investigated by thermomagnetic analysis and magnetometry. The results showed that the mass magnetization is stable when heated to 500°C. However, there is a marked increase in Curie temperature from 580 to 650°C, which can be explained by the formation of maghemite. When heated above 500°C, the magnetization begins to decrease and reaches its minimum value at 900°C, which indicates the formation of weakly magnetic …