The inexorable trend of spintronics is to develop efficient spin-control methods. For example, photovoltaic spintronics driven by sunlight has great potential in energy-saving applications. Here, a ferromagnetic/PV heterojunction is prepared on Si-substrate as Ta (4 nm)/Co (1 nm)/ZnO (from 10 to 58 nm)/ PTB7-Th: PC 71 BM/Pt (3 nm) to study how visible light affected magnetic dynamics. A linewidth variation as high as 812.55 Oe is achieved by optimizing the thickness of ZnO film used to enhance the electron transfer. Due to the photovoltaic effect, reversible ferromagnetic resonance (FMR) linewidth switches are displayed, which is attributed to the 3d orbitals occupancy of Co induced the TMS contribution and inhomogeneous broadening. This work proposes a sunlight controllable magnetic damping heterostructure for developing fast, small, energy-efficient spintronics applications.

Inorganic/organic dielectric composites with outstanding energy storage properties at a low electric field possess the advantages of low operating voltage and small probability of failure. Composites filled with two-dimensional inorganic nanosheets have attracted much attention owing to their fewer interfacial defects caused by the agglomeration of fillers. Continuous oxide films with a preferred orientation can play a significant role in enhancing energy storage. The challenge is to prepare large-sized, freestanding, single-crystal, ferroelectric oxide films and to combine them with polymers. In this work, a well-developed water-dissolvent process was used to transfer millimeter-sized (100)-oriented BaTiO3 (BTO) films. Poly­(vinylidene fluoride) (PVDF)-based heterojunctions sandwiched with the single-crystal films were synthesized via the transferring process and an optimized hot-pressing technique. By virtue of high ion displacement polarization and inhibited conductive path formation of single-crystal BTO films, the energy storage density and efficiency of BTO/PVDF heterojunctions reach 1.56 J cm–3 and 71.2% at a low electric field of 120 MV m–1, which are much higher than those of pure PVDF and BTO nanoparticles/PVDF composite films, respectively. A finite-element simulation was employed to further confirm the experimental results. This work provides an effective approach to enhance energy storage properties in various polymer-based composites and opens the door to advanced dielectric capacitors.

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Finding an energy‐efficient way of switching magnetization is crucial in spintronic devices, such as memories. Usually, spins are manipulated by spin‐polarized currents or voltages in various ferromagnetic heterostructures; however, their energy consumption is relatively large. Here, a sunlight control of perpendicular magnetic anisotropy (PMA) in Pt (0.8 nm)/Co (0.65 nm)/Pt (2.5 nm)/PN Si heterojunction in an energy‐efficient manner is proposed. The coercive field (HC) is altered from 261 to 95 Oe (64% variation) under sunlight illumination, enabling a nearly 180° deterministic magnetization switching reversibly with a 140 Oe magnetic bias assistant. The element‐resolved X‐ray circular dichroism measurement reveals different L3 and L2 edge signals of the Co layer with or without sunlight, suggesting a photoelectron‐induced redistribution of the orbital and spin moment in Co magnetization. The first‐principle calculations also reveal that the photo‐induced electrons shift the Fermi level of electrons and enhance the in‐plane Rashba field around the Co/Pt interfaces, leading to a weakened PMA and corresponding HC decreasing and magnetization switching accordingly. The sunlight control of PMA may provide an alternative way for magnetic recording, which is energy efficient and would reduce the Joule heat from the high switching current.

Traditional current‐driven spintronics is limited by localized heating issues and large energy consumption, restricting their data storage density and operation speed. Meanwhile, voltage‐driven spintronics with much lower energy dissipation also suffers from charge‐induced interfacial corrosion. Thereby finding a novel way of tuning ferromagnetism is crucial for spintronics with energy‐saving and good reliability. Here, a visible light tuning of interfacial exchange interaction via photoelectron doping into synthetic antiferromagnetic heterostructure of CoFeB/Cu/CoFeB/PN Si substrate is demonstrated. Then, a complete, reversible magnetism switching between antiferromagnetic (AFM) and ferromagnetic (FM) states with visible light on and off is realized. Moreover, a visible light control of 180° deterministic magnetization switching with a tiny magnetic bias field is achieved. The magnetic optical Kerr effect results further reveal the magnetic domain switching pathway between AFM and FM domains. The first‐principle calculations conclude that the photoelectrons fill in the unoccupied band and raise the Fermi energy, which increases the exchange interaction. Lastly, a prototype device with visible light control of two states switching with a 0.35% giant magnetoresistance ratio change (maximal 0.4%), paving the way toward fast, compact, and energy‐efficient solar‐driven memories is fabricated.