Co 0.6 Fe 0.4 O–Co 1.4 Fe 1.6 O 4 core–shell nanoparticles with colossal exchange bias

core-shell (CS) nanoparticles with a lattice-matched interface and strong exchange coupling. We investigate their temperature and field-dependent magnetic properties using time-of-flight neutron diffraction and magnetometry. These nanoparticles exhibit the highest reported EB values among core-shell nanoparticles, reaching a maximum of 10.34 kOe. Additionally, the core exhibits antiferromagnetism above room temperature, with a Néel temperature of approximately 397 K, making it more suitable for high-temperature applications. This study paves the way for designing core-shell biphasic nanoparticles to enhance the EB effect and tune the effective magnetic anisotropy, offering potential future applications in nanospintronics and nanomedicine.