Chiral Perovskite for next generation computing devices
Chiral materials have gained attention due to their unique properties, such as circular dichroism (CD) and chirality-induced spin selectivity (CISS), which are not observed in achiral materials. In particular, chiral perovskites are attracting interest because of their high charge mobility, strong light absorption coefficients, process compatibility, and strong spin-orbit coupling. Notably, the structural flexibility of chiral perovskites allows for easy tuning of desired properties. Therefore, after synthesizing chiral perovskites with specific characteristics, their CD and CISS effects can be measured to confirm the realization of these properties. Furthermore, by measuring not only CD and CISS but also other chiral properties, the physical mechanisms underlying chirality can be analyzed, leading to a deeper understanding of the material. This process ensures the material's practical applicability and further validates its potential for next-generation memory devices.
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Chiral Perovskite based MRAM
The chirality-induced spin selectivity (CISS) effect can be measured using a magnetoconductive AFM (MCP-AFM) system. In conventional MRAM, two ferromagnetic layers are used to create on/off states. To control the spin of the free layer, an external magnetic field is required, and the structure of the fixed layer is highly complex. Additionally, device miniaturization is challenging due to interference between adjacent devices. The CISS effect allows spin control via electrical current and does not respond to external magnetic fields, addressing these issues. Moreover, it is theoretically predicted to exhibit a higher spin polarization than conventional ferromagnetic materials.
We fabricated a chiral spin valve by replacing the fixed layer with chiral perovskite and confirmed that magnetoresistance (MR) can be enhanced by tuning the chiral material[1]. Additionally, by analyzing the angular momentum-dependent electron and magnon transport properties of chiral perovskites via the spin Seebeck effect, we aim to deepen our understanding of the CISS effect. Through this research, we seek to demonstrate that chiral perovskites offer a promising alternative to overcome the limitations of current MRAM technology.
[1] APL Mater. 12, 081118 (2024)