Infrared absorption of Nd2−xCexCuO4 and R2CuO4 (R=Pr, Nd, Sm, and Gd)

✍ Scribed by Masayuki Udagawa; Yoshinori Nagaoka; Tatefumi Johkou; Norio Ogita; Miki Masada; Jun Akimitsu; Kohji Ohbayashi

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 151 KB
• Volume: 194-196
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(94)90546-0

✦ Synopsis

Infrared absorption spectra of Nd2_~CexCuO4 and R2CuO4 (R=Pr, Nd, Sm, and Gd) have been measured in the energy region between 250 and 800cm-]at room temperature. For Nd2-xCexCuO4 , it is found that the mode at about 350cm-1, which is the vibration of oxygen in the R-O layers along the a-axis, disappears both for the as-grown Nd2_xCe,CuO4 of x>0.08 and for the oxygen-reduced Nd2-xCexCuO4 of x>0, and the disappearance is correlated to the resistivity. For R2CuO4 , it is found that the energy of the A2u symmetry mode, which is the oxygen vibration along the c-axis, increases by about 50cm-lbetween Pr to Gd, and this fact suggests that the three dimennsional character increases in a sequence of Pr, Nd, Sm, and Gd.