The impact of low-temperature heat treatment on the structural and magnetic properties of Pt-(Au-)-Co heterostructures

DOI: 10.62564/M4-RP2357

Roman Pedan¹, Pavlo Makushko², Yurii Yavorskyi¹, Oleksandr Dubikovskyi³, Andrii Bodnaruk⁴, Andrii Burmak¹, Denys Makarov², Igor Vladymyrskyi<sup>1

1</sup>Igor Sikorsky Kyiv Polytechnic Institute, Ukraine
²Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Germany
³V. Lashkaryov Institute of Semiconductor Physics of National Academy of Science of Ukraine
⁴Institute of Physics, National Academy of Sciences of Ukraine


Utilizing thermally induced diffusion-driven structural phase transformations in multilayer stacks to facilitate the formation of functional thin films holds significant promise for applications in nanoelectronics and magnetic data storage [1]. Ferromagnetic thin films derived from Co-Pt alloys serve as a foundational material science platform for the advancement of diverse applications, including spin valves, spin orbit torque devices, and high-density data storage media. In the present study Co(10 nm)/Pt(10 nm)/substrate, Pt(10 nm)/Co(10 nm)/substrate, Co(10 nm)/Au(2 nm)/Pt(10 nm)/substrate, and Pt(10 nm)/Au(2 nm)/Co(10 nm)/substrate stacks were obtained by magnetron sputtering onto SiO2/Si(001) substrate. The as-deposited stacks were annealed in a vacuum at temperatures of 150 °C – 550 °C for 30 minutes. Structural and magnetic properties were studied by secondary ion mass spectrometry (SIMS), X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and VSM magnetometry. Diffusion coefficients were estimated using the Hall–Morabito and Fisher–Whipple approaches. It is demonstrated that the layer stacking significantly impacts the diffusion rate at temperatures where the diffusion is dominated by grain boundaries. The heat treatment of thin-film stacks enhances coercivity, attributed to short-range chemical ordering effects. Introducing an additional Au intermediate layer increases the coercive field of annealed sstacks by modifying exchange coupling between magnetic grains at grain boundaries.

Keywords
diffusion coefficient, grain boundary diffusion, magnetic thin films, Co-Pt alloy

Acknowledgments
Not provided

References
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