Concomitant Magnetic Memory Effect in CrO2-Cr2O3 Core-Shell Nanorods: Implications for Thermal Memory Devices

The origin of the concomitant memory effect is still a controversial issue and poor evidence in the observation of nanocrystal systems. We report on a type of concomitant memory effect driven by first-field-induced unidirectional magnetic anisotropy at the interface of ferromagnetic CrO2-core and antiferromagnetic Cr2O3-shell nanorods, with the effect becoming less significant in pure CrO2 nanorods. To corroborate the results, a core-shell anisotropic energy model was used to determine the coherent rotation of magnetization and exchange coupling constant, giving direct access to the anisotropic interfacial properties of the core-shell nanoscale system without spatially resolved magnetic measurement. The outcome of this study will be useful for the future development of thermal memory devices.