High-pressure structural studies of Li x La1/3NbO3 (x = 1/6, 1/3, 1/2, 2/3)
- 200 Downloads
The high-pressure behavior of Li x La1/3NbO3 (x = 1/6, 1/3, 1/2, 2/3) perovskites where Li cations were substituted for the existing vacancies was studied using synchrotron X-ray diffraction. It was shown that all these materials undergo irreversible pressure-induced amorphization around 14.5 GPa regardless of the Li concentration. The Li-inserted materials were found to exhibit a standard pressure response (bulk modulus pressure derivative B 0′ ~4) when in the crystalline phase, whereas La1/3NbO3 shows a linear volume contraction versus pressure, i.e., B 0′ ~(−1). These results suggest that the structural collapse is not a consequence of cation disorder resulting from the Nb atoms (B-site) migrating to the A-site vacancies. The observed pressure response can be understood by increased occupancy of the A-sites opposing the tilting of the NbO6 octahedra. The pressure evolution of the Nb oxidation state is discussed.
KeywordsPressure-induced amorphization Perovskite Lanthanide oxides
Portions of this research were carried out at beamline P02.2 of the light source PETRA III at DESY, a member of the Helmholtz Association (HGF).
- Belous AG, Didukh IR, Novosadova EB, Pashkova EV, Khomenko BS (1990) Izv Akad Nauk SSSR. Neorg Mater 26:1294Google Scholar
- Galasso FS (1969) Structure, properties and preparation of perovskite-type compounds. Pergamon, OxfordGoogle Scholar
- Howard CJ, Zhang Z (2003) Structures and phase transition in the layered perovskite La0.6Sr0.1TiO3: a new orthorhombic structure solved from high-resolution diffraction in combination with group theoretical analysis. J Phys Condens Matter 15:4543. doi: 10.1088/0953-8984/15/26/304 CrossRefGoogle Scholar
- Mitchell RH (2002) Perovskites: modern and ancient. Almaz Press, Thunder BayGoogle Scholar
- Navrotsky A, Weidner DJ (1989) Perovskite: a structure of great interest to geophysics and material science. American Geophysical Union, WashingtonGoogle Scholar
- Noked O, Melchior A, Shuker R, Steininger R, Kennedy BJ, Sterer E (2013) Pressure-induced amorphization of A-site-deficient double perovskite Ln1/3MO3 (Ln = Pr, Nd, M = Nb, Ta). Phys Chem Min 1–9. doi: 10.1007/s00269-013-0622-4
- Rao CNR, Raveau B (1998) Transition metal oxides, 2nd edn. VCH, New YorkGoogle Scholar
- Tejuco LG, Fierro JLG (1993) Properties and applications of perovskite-type oxides. Marcel Dekker, New YorkGoogle Scholar
- Wakihara M, Guohua L, Ikuta H (1998) A review of positive electrode materials for lithium-ion batteries. In: Wakihara M, Yamamoto O (eds) Lithium ion batteries, chap 2. Kodansha, TokyoGoogle Scholar