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

Highlights: ► 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. -- Abstract: The effect of mechanical grinding and subsequent low temperature annealing on the orthorhombic to monoclinic structural transition in the Er5Si4 compound was studied by X-ray powder diffraction using both a conventional laboratory Cu Kα1 radiation and a high-energy synchrotron source. A reversible phase transition from the orthorhombic to monoclinic structure occurs as a result of mechanical grinding. Low temperature annealing reverses the transformation and converts the formed monoclinic phase back to the orthorhombic, evidently by relieving residual stress introduced during the grinding