Effects of mechanical grinding and low temperature annealing on crystal structure of Er5Si4

► Impurity phases exist in orthorhombic Er5Si4:monoclinic 5:4, 1:1 and 5:3. ► Mechanical grinding induces transition from orthorhombic 5:4 to monoclinic 5:4. ► Low temperature annealing reverses the monoclinic 5:4 to orthorhombic 5:4.