Realization of sub-10 nm spin-based logic and memory devices relies on the development of magnetic materials with perpendicular magnetic anisotropy that can provide low switching current and large thermal stability simultaneously. In this work, the authors report on one promising candidate, Fe16N2, a heavy-metal-free, non-interface perpendicular magnetic material and demonstrate a perpendicularly magnetized current-perpendicular-to-plane (CPP) giant magnetoresistance (GMR) device based on Fe16N2. The crystalline-based perpendicular anisotropy of Fe16N2 in the CPP GMR device is measured to be about 1.9 × 106 J m−3 (1.9 × 107 erg cm−3), which is sufficient to maintain the thermal stability of sub-10 nm devices. A first principle calculation is performed to support this large magnitude of the perpendicular anisotropy. Moreover, the Gilbert damping constant of the Fe16N2 thin film (α ≈0.01) measured by ferromagnetic resonance (FMR) is lower than for most existing materials with crystalline perpendicular magnetic anisotropy. The non-interface perpendicular anisotropy and low damping properties of Fe16N2 may offer a pathway for future spintronics logic and memory devices.
Bibliographical noteFunding Information:
X.L. and M.Y. contributed equally to this work. This work was partially supported by the DOE ARPA-E rare-earth-free magnet program and later the C-SPIN center, one of six STARnet program research centers, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA. Device fabrication was performed at the University of Minnesota Nanofabrication Center, which receives support from the National Science Foundation (NSF) through the National Nanotechnology Infrastructure Network program. Thin film characterization was performed at the University of Minnesota Characterization Facility, which has received capital equipment funding from the NSF through the Materials Research Science and Engineering Center. M.Y. thanks the support of China Scholar Council visiting Program.
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- damping constant
- giant magnetoresistance
- perpendicular magnetic anisotropy
- spintronic devices