Controlled spin-to-charge conversion in noncollinear antiferromagnet-based <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>Py</mml:mi> <mml:mo>/</mml:mo> <mml:mi>Mn</mml:mi> </mml:mrow> <mml:mn>3</mm

Noncollinear antiferromagnets (NCAFs) have recently emerged as promising candidates for future spintronic technologies, offering ultrafast switching, negligible stray fields allowing dense packing, and robustness against external magnetic perturbations. When interfaced with ferromagnets (FMs), they can strongly influence interfacial exchange and spin-torque mechanisms that enable manipulating magnetic order and realizing functionalities beyond conventional heavy metals (HMs) based FM/HM heterostructures. Here, we perform a broadband ferromagnetic resonance (FMR) study to systematically investigate the magnetization dynamics and spin-to-charge conversion in permalloy (Py) and ${\mathrm{Mn}}_{3}\mathrm{Pt}$ bilayers. High-quality Py films provide well-defined FMR spectra with a low Gilbert damping parameter (${\ensuremath{\alpha}}_{\mathrm{eff}}\ensuremath{\approx}9.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$). We observe a pronounced enhancement of damping with intrinsic value ${\ensuremath{\alpha}}_{\mathrm{int}}\ensuremath{\approx}3.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$ in the $\mathrm{Py}/{\mathrm{Mn}}_{3}\mathrm{Pt}$ bilayer, indicating efficient spin pumping into the NCAF layer. Frequency dependent linewidth analysis shows a predominantly Gilbert type damping in the bilayers and the corresponding effective spin-mixing conductance (${g}_{\mathrm{eff}}^{\ensuremath{\uparrow}\ensuremath{\downarrow}}\ensuremath{\approx}4.8\ifmmode\times\else\texttimes\fi{}{10}^{18}\phantom{\rule{0.28em}{0ex}}{\mathrm{m}}^{\ensuremath{-}2}$) is comparable to that of other high-performance antiferromagnetic heterostructures. These results are significant for establishing NCAFs as a candidate material for spin generation and highlight the potential of $\mathrm{Py}/{\mathrm{Mn}}_{3}\mathrm{Pt}$ bilayers for efficient and ultrafast spintronic applications.