[22a-E204-1~9] 6.3 Oxide electronics

△ [22a-E204-9] Synthesis and optical properties of single-crystalline pyrochlore A₂²⁺B₂⁵⁺O₇ (A = Sn, Pb; B = Nb, Ta) thin films

〇(M2)Hiroaki Ito¹, Takahiro Fujita¹, Masashi Kawasaki^1,2 (1.Univ. of Tokyo, 2.RIKEN CEMS)

Keywords:Pulsed laser deposition, Pyrochlore, Optical measurement

Pyrochlore oxides A₂²⁺B₂⁵⁺O₇ (A = Sn, Pb; B = Nb, Ta) are expected to have a ‘quasi flat band structure’ near Fermi level, which can be a source of intriguing physical properties such as ferromagnetism without magnetic elements when holes are heavily doped. We have prepared single crystal A₂²⁺B₂⁵⁺O₇ films by pulsed laser deposition on Y-stabilized ZrO2(111) substrate. While Sn₂B₂O₇ single crystal films were fabricated at the temperature of 450 ℃ and the O₂ pressure of 1×10^-4 Torr, growth window of Pb₂B₂O₇ single crystal films were found at the temperature of 300 ℃ and the O₂ pressure of 1 Torr because of larger vaporability of PbO than of SnO. Spectroscopy measurements found relative positions of energy levels near Fermi level of A₂²⁺B₂⁵⁺O₇.