arXiv subjects

Li-Juan Yang

Publications and source records attributed to Li-Juan Yang.

2 recordsLinked to original sources

arXiv2015

First-principles study of the relaxor ferroelectricity of Ba(Zr,Ti)O$_3$

Ba(Zr,Ti)O$_3$ is a lead-free relaxor ferroelectric. Using the first-principles method, the ferroelectric dipole moments for pure BaTiO$_3$ and Ba(Zr,Ti)O$_3$ supercells have been studied. All possible ion configurations of BaZr$_{0.5}$Ti$_{0.5}$O$_3$ and BaZr$_{0.25}$Ti$_{0.75}$O$_3$ are constructed in a $2\times2\times2$ supercell. For the half-substituted case, divergence of ferroelectric properties has been found among these structures, which seriously depends on the arrangement of Ti and Zr ions. Thus our results provide a reasonable explanation to the relaxor behavior of Ba(Zr,Ti)O$_3$. In addition, a model based on the thermal statistics gives the averaged polarization for Ba(Zr,Ti)O$_3$, which depends on the temperature of synthesis. Our result is helpful to understand and tune the relaxor ferroelectricity of lead-free Ba(Zr,Ti)O$_3$.

cond-mat.mtrl-sci↗

arXiv2014

Strain driven sequential magnetic transitions in strained GdTiO3 on compressive substrates: a first-principles study

The compressive strain effects on the magnetic ground state and electronic structure of strained GdTiO 3 have been studied by the first-principles method. Different from the congeneric YTiO3 and LaTiO3 cases both of which becomes the A-type antiferromagnetism on the (001) LaAlO3 substrate despite their contrastive magnetism, the ground state of strained GdTiO3 on the LaAlO3 substrate changes from the original ferromagnetism to G-type antiferromagnetim, instead of the A-type one although Gd 3+ is between Y3+ and La3+. Only when the in-plane compressive strain is large enough, e.g. on the (001) YAlO3 substrate, the ground state finally becomes the A-type one. The band structure calculation shows that these compressive strained GdTiO3 remain insulating, although the band gap changes a little in these strained GdTiO3.

cond-mat.mtrl-sci↗