Experimental and theoretical study of α-Eu2(MoO4)3 under compression

Area of Science:

• Solid State Chemistry
• Materials Science
• High-Pressure Physics

Background:

• Europium trimolybdate (α-Eu2(MoO4)3) is a material with potential applications requiring understanding its behavior under pressure.
• Previous studies on related trimolybdates and tritungstates show different compression and amorphization mechanisms.

Purpose of the Study:

• To investigate the compression process and amorphization of α-Eu2(MoO4)3 up to 21 GPa.
• To elucidate the structural changes and phase transitions under high pressure using experimental and theoretical methods.

Main Methods:

• X-ray diffraction (synchrotron and laboratory sources)
• Raman scattering
• Photoluminescence spectroscopy
• First-principles density functional theory calculations

Main Results:

• Isotropic compression of the crystal structure below 8 GPa.
• Anisotropic compression between 8 and 12 GPa, driven by MoO4 tetrahedra distortion and rotation.
• Amorphization initiated above 12 GPa without prior crystalline-crystalline phase transitions.

Conclusions:

• The compression and amorphization of α-Eu2(MoO4)3 follow a distinct three-stage process.
• This behavior contrasts with the compression mechanisms observed in β-phase trimolybdates and α-phase tritungstates.