Unusual crystal structure evolution, multiple phase boundaries and phase coexistence in (1 -...

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• Understanding material functionality relies on crystal structure.
• The Ba(Cu1/3Nb2/3)O3-PbTiO3 solid solution is a new system with potential for tunable properties.

Purpose of the Study:

• To investigate the room temperature crystal structures of the (1 - x)Ba(Cu1/3Nb2/3)O3-(x)PbTiO3 solid solution across its entire compositional range.
• To identify and characterize different crystallographic phases and phase coexistence regions within this solid solution.

Main Methods:

• High-resolution X-ray diffraction (XRD) data was collected.
• Rietveld analysis was employed to confirm crystal structure symmetry.
• Lattice parameters and unit cell volume variations were analyzed.

Main Results:

• New cubic and monoclinic crystal structures were discovered, alongside the parent tetragonal phases.
• Multiple phase boundaries were identified, including cubic, tetragonal, and monoclinic phases.
• Specific composition ranges exhibited unique phase coexistences, such as two tetragonal phases or coexisting cubic and tetragonal phases.

Conclusions:

• The Ba(Cu1/3Nb2/3)O3-PbTiO3 solid solution exhibits complex crystallographic behavior with multiple phase transitions.
• The presence of diverse phases and wide compositional phase boundaries makes this system promising for tuning material properties.