Research Article Investigation of Phonon Vibrational Modes in Ga, Al, Fe, Co, Ni, and Zn Doped (110)-Oriented PBCO Thin Films Hom Kandel , 1 Milko Iliev, 2 Nathan Arndt, 1 and Tar-Pin Chen 3 1 Department of Physics, University of Wisconsin-Parkside, Kenosha, WI 53144, USA 2 Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA 3 Department of Physics and Astronomy, University of Arkansas, Little Rock, AR 72204, USA Correspondence should be addressed to Hom Kandel; kandel@uwp.edu Received 9 March 2020; Accepted 9 June 2020; Published 28 June 2020 Academic Editor: Alicia E. Ares Copyright © 2020 Hom Kandel et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We performed Raman scattering measurements and a comprehensive study of different types of Raman modes associated with phonon vibrations on pure and Ga, Al, Fe, Co, Ni, and Zn doped (110)-oriented PrBa 2 Cu 3 O 7 (PBCO) thin films to identify the substitution of Cu (1) or Cu (2) ions in PBCO lattice. In Raman spectrum of (110)–oriented PBCO thin film, we observed four prominent A g type Raman modes at ∼130 cm −1 , ∼150 cm −1 , ∼440 cm −1 , and ∼520 cm −1 corresponding to Ba, Cu (2), O (2)–O (3) in-phase, and O (4) apical oxygen vibration along c-axis, respectively. e Raman mode of pure PBCO at ∼520 cm −1 softened on Ga, Al, Fe, and Co doped PBCO thin films while it remained unaffected on Zn and Ni doped PBCO thin films. We explain these results in the context of their correlation with Cu (1)–O (4) and Cu (2)–O (4) bond lengths. In addition, we observed a new Raman mode near 610 cm −1 in the Raman spectra of Ga, Al, Fe, and Co doped PBCO thin films, an infrared (IR) active mode that became Raman active when the symmetry was broken at the Cu-O chain site after the partial substitution of Cu (1) ion. Moreover, the “O (2)–O (3) in-phase Raman mode” near 440 cm −1 remained unaffected in Fe, Co, Ga, and Al doped PBCO thin films but softened in Zn and Ni doped PBCO thin films. Based on these results, we argue that Ga, Al, Fe, and Co ions replace Cu (1) ion at the Cu-O chain site, break the crystal symmetry, and produce disorder locally, whereas Zn and Ni ions replace Cu (2) ion at the CuO 2 plane of the PBCO lattice structure. 1. Introduction Raman spectroscopy is an ideal analytical tool for site de- tection of Cu ion substitution in the family of cuprate oxide compound RBa 2 Cu 3 O 7 (R � Rare Earth element). Two of the most useful members of this family are high critical tem- perature (T c ) superconductor YBa 2 Cu 3 O 7−δ (YBCO) and cuprate oxide insulator PrBa 2 Cu 3 O 7−δ (PBCO), which share similar lattice structure and oxygen chemistry [1] and are used in wide range of superconducting electronic and magnetic devices. e substitution of Pr for Y in Y 1−x Pr x Ba 2 Cu 3 O 7−δ suppresses T c with superconductivity disappearing for x > �0.50 [2]. Substitutions of Cu ions in PBCO by trivalent metal ions such as Fe, Co, Ga, and Al and divalent metal ions such as Ni and Zn are of special interest in applied superconductivity and materials science as these elements have preferential role in the substitution of Cu ions, i.e., from the Cu-O chains or CuO 2 planes of PBCO lattice. Raman spectroscopy is one of the many tools to detect the Cu ion sites of the substituted trivalent or divalent ions. As shown in Figure 1, the unit cell of PBCO is either tetragonal or orthorhombic, which contains two dimpled Cu (2)–O (2)-O (3) planes (CuO 2 planes), separated by a single Pr atom that form a two-dimensional rectangular network. e O (1) atoms along the b-axis direction (y-axis in Fig- ure 1) form the Cu (1)–O (1) chains at the top or bottom of the each unit cell. ere are no equivalent oxygen atoms along a-axis direction (x-axis direction in Figure 1) and hence no Cu (1)–O (1) chain in this direction. O (4) oxygen forms a bridge between the Cu (1) and Cu (2) ions. X-ray and neutron diffraction measurements performed on the metal- doped PBCO powder samples, namely, PrBa 2 [Cu 1−x M x ] 3 O 7 Hindawi Advances in Materials Science and Engineering Volume 2020, Article ID 5937494, 8 pages https://doi.org/10.1155/2020/5937494