Using a layered approach to increase magnetoresistance in MRAM junctions
Using a layered approach to increase magnetoresistance in MRAM junctions lead image
A promising alternative to existing computer memory is magnetic RAM, or MRAM. This type of memory stores data using magnetic spin and offers several advantages over existing memory technologies. To become viable, MRAM materials must exhibit specific properties, including high magnetoresistance, strong data retention, and fast switching times.
Khanal et al. developed a structure that meets most of these conditions. In tests, their material exhibits high magnetoresistance and is likely to achieve fast switching times as well. More broadly, their research could result in versatile materials that meet most or all of the necessary criteria.
“These results demonstrated that high magnetoresistance and strong retention can be obtained,” said author Weigang Wang. “More importantly, high switching speed can potentially also be achieved.”
The discovery made use of multi-interface free layers (MIFLs), which incorporate multiple materials with different properties. Using these layers, the researchers adjusted the magnetoresistance and data retention separately by employing different materials for each purpose.
The researchers discovered they could layer ferromagnetic CoFeB with nonmagnetic Mo or MgO and alter the magnetoresistance by changing the thickness of the CoFeB layer. In tests, they managed to demonstrate a magnetoresistance of over 200%.
Next, the study’s authors are planning to probe the switching capability of their MIFL design. An ideal MRAM junction must be able to switch states quickly and using little energy.
“With these encouraging results, now studies are underway to characterize the switching behavior,” said Wang. “We are trying to understand the switching mechanism and ultimately achieve ultralow energy switching in these devices.”
Source: “Perpendicular magnetic tunnel junctions with multi-interface free layer,” by Pravin Khanal, Bowei Zhou, Magda Andrade, Yanliu Dang, Albert Davydov, Ali Taha Habiboglu, Jonah Saidian, Adam Laurie, Jian-Ping Wang, Daniel B. Gopman, and Weigang Wang, Applied Physics Letters (2021). The article can be accessed at https://doi.org/10.1063/5.0066782 .
