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Negative temperature coefficient of Gilbert damping in magnetic bilayers

Lulu Cao1,2,3,4, Yuting Gong5, Xianyang Lu3,4, Yongbing Xu3,4,5, Ya Zhai1,*, Jing Wu2,†, Roy W. Chantrell2, and Richard F. L. Evans2,‡

  • 1Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing 211189, China
  • 2School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom
  • 3National Key Laboratory of Spintronics, Nanjing University, Suzhou 215163, China
  • 4School of Integrated Circuits, Nanjing University, Suzhou 215163, China
  • 5Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China

  • *Contact author: yazhai@seu.edu.cn
  • †Contact author: jing.wu@york.ac.uk
  • ‡Contact author: richard.evans@york.ac.uk

Phys. Rev. B 113, L220409 – Published 22 June, 2026

DOI: https://doi.org/10.1103/qc2z-thq5

Abstract

The Gilbert damping of magnetic materials is an important magnetic parameter that determines the switching speed and energy dissipation of spintronic devices. In simple metals, the intrinsic Gilbert damping increases with temperature and diverges near the Curie temperature as a result of spin fluctuations. Here we present atomistic simulations and experimental measurements showing surprising and opposite behavior in Py/Nd bilayers, where the Gilbert damping decreases with increasing temperature. The effect arises because of the enhanced damping at the interface as a result of spin pumping, where elevated temperatures cause a dynamic separation of the interfacial and bulk magnetization during relaxation. Furthermore, the temperature dependence of the damping can be controlled by varying the thickness of the Nd capping layer. Our findings present a spintronic effect that can be used to modify the dynamic properties of nanoscale materials and devices for enhanced energy efficiency or with improved switching dynamics.

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