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Disorder-enhanced spin Hall effect in Ru-Pt alloy thin films

Vineetha S. Bheemarasetty 1,*,‡, Xinhao Wang2,‡, Shreya Shrestha3, M. Benjamin Jungfleisch3, Lars Gundlach2,4, John Q. Xiao2, and Gang Xiao1,†

  • *Contact author: vineetha_bheemarasetty@brown.edu
  • †Contact author: gang_xiao@brown.edu
  • ‡These authors contributed equally to this work.
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Phys. Rev. Applied 26, 014030 – Published 10 July, 2026

DOI: https://doi.org/10.1103/hvn3-gjfy

Abstract

The search for material systems exhibiting a large spin Hall effect is central to the development of ultrafast, energy-efficient spintronic technologies. We systematically investigate the spin Hall angle (SHA) in Ru-Pt binary alloys using three complementary techniques: spin-torque magneto-optic Kerr effect, spin-torque ferromagnetic resonance, and time-domain terahertz emission spectroscopy. Within the measured composition range, a maximum SHA of 0.158 is observed in Ru38Pt62, representing a 56% enhancement over Pt while maintaining a resistivity below 70  μΩ cm. Notably, these high SHA values are achieved in as-grown sputtered films across the full composition range without the need for complex fabrication procedures or high-temperature annealing. These results establish Ru-Pt as a scalable model alloy system in which composition-driven disorder, together with gradual structural evolution, governs spin-charge conversion, providing a practical pathway for optimizing materials for spin-orbit torque devices.

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Phys. Rev. Applied 26, 014030– Published 10 July, 2026
  • Received 15 October 2025
  • Revised 20 April 2026
  • Accepted 27 May 2026
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