Role of spin-phonon and electron-phonon interactions in the phonon renormalization of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mi>Eu</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Bi</mml:mi><mml:mi>x</mml:mi></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Ir</mml:mi><mml:mn>2</mml:mn></mml:…

We report temperature-dependent Raman scattering and X-ray diffraction studies of pyrochlore iridates, (Eu$_{1-x}$Bi$_x$)$_2$Ir$_2$O$_7$, for x=0, 0.02, 0.035, 0.05 0.1. The temperature variation in experiments spans from 4 K to 300 K, covering the metal-insulator phase transition accompanied by paramagnetic all-in/all-out (AIAO) spin ordering (T$_N$). These systems also show a Weyl semi-metal (WSM) at low temperatures (below ~50 K). that Ir-O-Ir bond bending mode, A$_{1g}$ (510 cm$^{-1}$), shows anomalous softening magnetically ordered AIAO state, arising primarily spin-phonon interaction due phonon-modulation Dzyaloshinskii-Moriya (DM) spin-exchange interaction. two stretching modes, T$_{2g}^1$ (307 cm$^{-1}$) T$_{2g}^2$ (382 harden significantly magnetic insulating phase. T$_{2g}$ phonons dependence their mode frequencies, hitherto unreported, strong electron-phonon coupling. signatures WSM state are observed phonon renormalization below 50 Our experimental results establish magneto-elastic coupling T$_N$ significant interactions metallic above as well low-temperature state.