Large reversible magnetostrictive effect in the Gd 1− x Sm x Mn 2 Ge 2 ( x =0.37,0.34) alloys at room temperature

•Thermal- and magnetic-field-induced magnetoelastic transitions are obtained at room temperature.•The transition is proved to be accompanied with large lattice distortion.•Large reversible magnetostriction with minimal hysteresis is obtained at room temperature.•The observed magnetostrain shows high stability.