Photo-Controlled Exchange Bias in CoO@Co-Fe PBA Core-Shell Heterostructure

Regulating the exchange bias (EB) effect via an external field allows one to effectively tailor the properties of the spin-valve-based spintronic devices. However, as a reliable way to manipulate the magnetic properties of materials, there are few reports on the effect of light irradiation on the exchange bias effect so far. In this work, a non-volatile light-tunable EB is achieved in a well-designed CoO@Co-Fe PBA core-shell structure, where the antiferromagnetic CoO has a large anisotropy, and the molecular magnet Co-Fe PBA has the characteristics of photosensitive. The exchange bias field of this hybrid can be permanently reduced by ~ 50% after an irradiation of 20 minutes, and the reduction degree will change by futher tunning the irradiation time. In addition, the switching of the two EB effect states can also be successfully implemented by switching red and blue light irradiation. Herein, this interesting tuning of EB effect is attributed to the formation of the photoinduced FeIII - CoII magnetic pairs in the photosensitive shell after light irradiation and the corresponding change of exchange coupling between the interface. Apparently, this striking light-controlled EB effect opens up new prospects for the design of new-generation optoelectronic devices.