Energy-Efficient <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:msub><mml:mi mathvariant="normal">W</mml:mi><mml:mrow><mml:mn>100</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Ta</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:mo>/</mml:mo></mml:math> Co-Fe-B/MgO Spin Hall Nano-Oscillators

We investigate a W-Ta alloying route to reduce the auto-oscillation current densities and power consumption of nano-constriction based spin Hall nano oscillators. Using spin-torque ferromagnetic resonance (ST-FMR) measurements on microbars W$_{\text{100-x}}$Ta$_{\text{x}}$(5 nm)/CoFeB(t)/MgO stacks with t = 1.4, 1.8, 2.0 nm, we measure substantial improvement in both spin-orbit torque efficiency conductivity. demonstrate 34\% reduction threshold density, which translates into 64\% as compared pure W-based SHNOs. Our work demonstrates promising aspects for energy-efficient operation emerging spintronic devices.