Research of magnetic properties of nanocrystalline materials considering temperature effects

Nanocrystalline materials are increasingly used in high-frequency transformer cores due to their advantages, including high permeability, high saturation flux density, and low loss characteristics. Measuring the magnetic properties of these materials at various temperatures is essential for accurately simulating loss distributions in high-frequency transformers and developing effective models. However, previous research on the measurements of nanocrystalline materials typically considered only a limited number of influencing factors and magnetic characteristic parameters, making it difficult for the findings to accurately reflect the impact of temperature on these materials. Therefore, this paper introduces a temperature-variable magnetic property measurement system for nanocrystalline magnetic rings based on a temperature-controlled chamber. This system is specifically designed to measure multiple property parameters, including saturation flux density, relative permeability, coercivity, and remanence, while accounting for several influencing factors, such as temperature, frequency, flux density, and excitation signals. Experimental measurements revealed positive correlations between the core loss, coercivity, and phase angle of the nanocrystalline material with temperature, while its saturation flux density and relative permeability showed negative correlations with temperature. In addition, a complex relationship was observed between the remanence and temperature across different flux density ranges, and the variation trends of magnetic properties in the saturation range were further identified. These results provide valuable data for developing loss models and optimizing the design of high-frequency transformers.