Measurement of elliptic flow of light nuclei at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msqrt><mml:msub><mml:mi>s</mml:mi><mml:mrow><mml:mi>N</mml:mi><mml:mi>N</mml:mi></mml:mrow></mml:msub></mml:msqrt><mml:mo>=</mml:mo><mml:mn>200</mml:mn></mml:mrow></mml:math>, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV at the BNL Relativistic Heavy Ion Collider

We present measurements of second-order azimuthal anisotropy $({v}_{2})$ at midrapidity $(|y|&lt;1.0)$ for light nuclei $d,\phantom{\rule{0.16em}{0ex}}t,\phantom{\rule{0.16em}{0ex}}^{3}\mathrm{He}$ (for $\sqrt{{s}_{NN}}=200$, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and antinuclei $\overline{d}$ ($\sqrt{{s}_{NN}}=200$, 62.4, 39, 27, and 19.6 GeV) and $^{3}\overline{\mathrm{He}}$ ($\sqrt{{s}_{NN}}=200$ GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The ${v}_{2}$ for these light nuclei produced in heavy-ion collisions is compared with those for $p$ and $\overline{p}$. We observe mass ordering in nuclei ${v}_{2}({p}_{T})$ at low transverse momenta (${p}_{T}&lt;2.0$ GeV/$c$). We also find a centrality dependence of ${v}_{2}$ for $d$ and $\overline{d}$. The magnitude of ${v}_{2}$ for $t$ and $^{3}\mathrm{He}$ agree within statistical errors. Light-nuclei ${v}_{2}$ are compared with predictions from a blast-wave model. Atomic mass number $(A)$ scaling of light-nuclei ${v}_{2}({p}_{T})$ seems to hold for ${p}_{T}/A&lt;1.5\phantom{\rule{4pt}{0ex}}\mathrm{GeV}/c$. Results on light-nuclei ${v}_{2}$ from a transport-plus-coalescence model are consistent with the experimental measurements.