  Topological insulators have emerged as an important material class for
efficient spin-charge interconversion. Most topological insulators considered
to date are binary or ternary compounds, with the exception of $\alpha$-Sn.
Here we report a comprehensive characterization of the growth, magnetotransport
properties, and current-induced spin-orbit torques of $\alpha$-Sn and
$\beta$-Sn-based ferromagnetic heterostructures. We show that $\alpha$-Sn grown
with a Bi surfactant on CdTe(001) promotes large spin-orbit torques in a
ferromagnetic FeCo layer at room temperature, comparable to Pt, whereas
$\alpha$-Sn grown without Bi surfactant and the non-topological phase,
$\beta$-Sn, induce lower torques. The dampinglike and fieldlike spin-orbit
torque efficiency in $\alpha$-Sn with Bi are 0.12 and 0.18, respectively.
Further, we show that $\alpha$-Sn grown with and without Bi presents a spin
Hall-like magnetoresistance comparable to that found in heavy metal/ferromagnet
bilayers. Our work demonstrates direct and efficient charge-to-spin conversion
in $\alpha$-Sn ferromagnetic heterostructures, showing that $\alpha$-Sn is a
promising material for current-induced magnetization control in spintronic
devices.
