Tunneling magnetoresistance in ferromagnet/organic-ferromagnet/metal junctions*Project supported by the National Natural Science Foundation of China (Grant Nos. 11974215, 11704230, 11674197, and 11874242), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2019MA043), and the Taishan Scholar Project of Shandong Province, China.

Abstract

Spin-dependent transport in ferromagnet/organic-ferromagnet/metal junctions is investigated theoretically. The results reveal a large tunneling magnetoresistance up to 3230% by controlling the relative magnetization orientation between the ferromagnet and the central organic ferromagnet. The mechanism is explained by distinct efficient spin-resolved tunneling states in the ferromagnet between the parallel and antiparallel spin configurations. The key role of the organic ferromagnet in generating the large magnetoresistance is explored, where the spin selection effect is found to enlarge the difference of the tunneling states between the parallel and antiparallel configurations by comparing with the conventional organic spin valves. The effects of intrinsic interactions in the organic ferromagnet including electron–lattice interaction and spin coupling with radicals on the magnetoresistance are discussed. This work demonstrates a promising potential of organic ferromagnets in the design of high-performance organic spin valves.