Efficient control of magnetization in ferromagnets is crucial for highperformance

spintronic devices. Magnons offer a promising route to achieve

this objective with reduced Joule heating and minimized power consumption.

While most research focuses on optimizing magnon transport with minimal

dissipation, we present an unconventional approach that exploits magnon

dissipation for magnetization control, rather than mitigating it. By combining

a single ferromagnetic metal with an antiferromagnetic insulator that breaks

symmetry in spin transport across the layers while preserving the symmetry in

charge transport, we realize considerable spin-orbit torques comparable to

those found in non-magnetic metals, enough formagnetization switching. Our

systematic experiments and comprehensive analysis confirm that our findings

are a result of magnonic spin dissipation, rather than external spin sources.

These results provide insights into the experimentally challenging field of

intrinsic spin currents in ferromagnets, and open up possibilities for developing

energy-efficient devices based on magnon dissipation.

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