ORIGINAL RESEARCH PAPER SYNTHESIS OF STRONTIUM COPPER OXIDE WITH SUBSTITUTION OF RARE EARTH ELEMENTS P. Suardana Department of Physics, Udayana University, Denpasar, Indonesia K.N. Suarbawa Department of Physics, Udayana University, Denpasar, Indonesia G.N. Sutapa Department of Physics, Udayana University, Denpasar, Indonesia W.G. Suharta* Department of Physics, Udayana University, Denpasar, Indonesia *Corresponding Author ABSTRACT In this research have successfully synthesized Sr Eu Cu O superconductors with x are 0, 0.05, 0.10, 0.15 and 0.20. The synthesis process of Sr 1-x x 1 z 1- Eu Cu O superconductors uses SrCO (99.9%), Eu O (99.9%) and CuO (99.9%) materials. The sample synthesis process uses a wet-mixing x x 1 z 3 2 3 method, wherein the starting material is added strongly HNO acid, then stirred and heated to a crust. The calcination process was carried out at 3 o 600 C for 3 hours and sintered at 950°C for 3 hours. To know the success of sample synthesis, the first is X-ray diffraction (XRD) characterization to know the phases formed in the sample, lattice parameter values and unit cell volume. Second, the characterization of Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) to know particle size and precision of particle composition that have been made. Third, the characterization of Fourier Transform Infrared Spectroscopy (FTIR) is done to find out the frequency of vibration that occurs in the sample. The XRD characterization results show a sharp and separate spectrum with each other indicating that there has been a very good crystal formation. The addition of the Eu has resulted decreasing of lattice parameter of a-axis from 3.5828 to 3.5724 Å, lattice parameter of b-axis from 16.3308 to 16.3142 Å and lattice parameter of c-axis from 3.9135 to 3.9083 Å. That is caused ion radius of Eu is smaller than ion radius of Sr. The addition of doping of rare earth elements leads to the growth of new crystals containing rare earth elements with an increasing percentage in accordance with o the addition of these elements, that is Sr Eu Cu O compound at an angle 32.5 , in line with a decreasing peak intensity of SrCuO compound at an 1-x x 1 z z o angle 31.8 . The result of crystal size of the sample is obtained about 185-213 nm. The addition of the Eu element to the Sr Eu Cu O 1-x x 1 z superconductor causes the particle size to grow smaller. Fourier Transform Infrared Spectroscopy (FTIR) characterization results for all samples are shown in Figure 4.15. In general, the results show absorption waves at wave numbers 428.20, 858.32, 1188.15, 1460.11, 1714.72, 2210.42, -1 2499.75, 2735.06, 3005.10, 3290.56 cm . KEYWORDS Strontium Copper Oxide, Rare Earth, wet-mixing method 1. Introduction SrCuO superconductors are of concern to current researchers because 2 they have a high critical temperature of about 135 K. The SrCuO 2 compounds composed of CuO layers are only separated by Sr. alkaline 2 earth ions called infinite-layer compounds [M.G. Smith 1991]. The research of SrCuO superconductor continues to be carried out, either 2 by elemental substitution, doping treatment or attempting a new synthesis method, to produce SrCuO superconductors with single 2 phase, homogeneity, critical temperature, critical current density and high critical magnetic fields. Research with the substitution of La elements and high pressure has been done by Jung and his friends [C.U. Jung 2001], substitutions with Ru and Gd elements in ruthenium copper oxides with an annealing treatment of O have been reported by Awana, Takagiwa and 2 colleagues [V.P.S. Awana 2002; H. Takagiwa 2001]. In addition to elemental substitution variations, the study also focused on variations in the use of synthesis methods. Several methods of synthesis have been done by previous researchers such as solid state reaction method and melting method. The method of solid state reacts with melting method has been done by Awana and his friends [V.P.S. Awana 2003] to synthesize magneto-superconducting compounds at a temperature of o 1200 C and a pressure treatment of about 6 GPa. While the growth of La Ce CuO crystals has been observed using the method of Traveling 2-x x 4 Solvent Floating Zone (TSFZ) by Kunihiko and collegous [Kunihiko Oka 2003]. The synthesis process using these methods of course requires high costs and special equipment to produce samples of good quality. In this research the synthesis process is done by wet-mixing method to decrease the temperature of calcination and sintering, and substitution of rare earth element (Eu) to form the Sr Eu CuO superconductor in 1-x x z powder form. All synthesis process is done by wet-mixing method and nitric acid (HNO ) as a digest agent. The purpose of this research is to 3 know the change of Sr Eu CuO superconductor crystal structure 1-x x z without going through melting process and high pressure. Besides, to know and know the effect of substitution of rare earth element on Sr 1- Eu CuO superconductor crystal structure. The use of wet mixing x x z method has been done to synthesize various superconductors. The synthesis of REBaCuO superconductors with the addition of HNO as 3 digest agent has been done by Suharta and collegous [WG Suharta 2013] and synthesis of superconductor (NdLa) BaCuO with the addition of B O flux using wet mixing method has also been done by 2 3 Suharta and collegous [WG Suharta 2016]. 2. Experiment The materials used in this study were Sr CO (99.9%), Eu O (99.9%), 2 3 2 3 Gd O (99.9%) and CuO (99.9%). The synthesis process uses a wet- 2 3 mixing method with nitric acid (HNO3) as a digest agent. The steps of the synthesis process of Sr Eu CuO superconductors, 1-x x z starting from material weighing, wet mixing method, calcination and sintering is shown in the figure 1. Figure 1. Process flow diagram of Sr Eu CuO superconductor 1-x x z synthesis INTERNATIONAL JOURNAL OF SCIENTIFIC RESEARCH Physics 52 International Journal of Scientific Research Volume-7 | Issue-2 | February-2018 | PRINT ISSN No 2277 - 8179