Effect of Temperature and Time of Sintering to Doping Ag On Microstructure of Perovskite Material (La 1-x

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1 Journal of Physics: Conference Series PAPER OPEN ACCESS Effect of Temperature and Time of Sintering to Doping Ag On Microstructure of Perovskite Material (La 1-x Ag x ) 0.8 Ca 0,2 MnO 3 To cite this article: B Kurniawan et al 2018 J. Phys.: Conf. Ser View the article online for updates and enhancements. This content was downloaded from IP address on 10/10/2018 at 17:54

2 Effect of Temperature and Time of Sintering to Doping Ag On Microstructure of Perovskite Material (La 1-x Ag x ) 0.8 Ca 0,2 MnO 3 B Kurniawan 1*, S D Rosanti 1, R Kamila 1, N B Sahara 1, D S Razaq 1, E P Yandra 1 and T Komala 1 Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Depok 16424, Indonesia *Corresponding author: bkuru@fisika.ui.ac.id Abstract. Particle synthesis has been performed on perovskite material (La 1-x Ag x ) 0.8 Ca 0,2 MnO 3 using the sol-gel method. Bulk samples were varied in temperature and time of sintering and doping variations of Ag x 0 and x 0.5. Calculation of stoichiometry was done to get the mass of each precursor. Precursors were included La 2 O 3, AgNO 3, Ca(NO 3 ) 2.4H 2 O and Mn(NO 3 ) 2.4H 2 O. Sintering temperature variations were done at 650 o C for 5 hours and 900 o C for 24 hours. Scanning Electron Microscopy (SEM) was done to see sample morphology with secondary electron mode (SE), homogeneity with backscattered electron mode (BSE) and specify elements contained in the sample with semi-quantitative EDX properties. The SEM-EDX results show the characterization of samples depend on density, porosity, and granular morphology. Microstructures of perovskite materials have a better characterization at doping x 0.5 and at the highest temperature and sintering time. 1. Introduction Perovskite manganites are ones of the fascinating materials in condensed-matter research, because of their electrical and magnetic properties [1]. Substituting the Ln site by alkali earth or alkali element (A) in order to form Ln 1-y A y MnO 3 (La = trivalent rare earth element and A = alkaline earth) compounds exhibits unusual physical effects around their ferromagnetic (FM) paramagnetic (PM) phase-transition temperature (T C ). The unusual effects were such as microstructure, transport properties, colossal magnetoresistance and magnetocaloric (MCEs) [2-6]. The ionic radii of La 3+ and Ag + can incorporate into the lattice and substitute La ions, and the Ln site disorder induce by Ag substitution gives effect on microstructure. The application of perovskite LCMO is in the fields of magnetic memory devices, refrigeration, sensor, biology, medicine, and catalyst [7]. Physical properties of manganites may be modified by the chemical composition as well as by various treatments affecting their microstructure [8-9]. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by Ltd 1

3 In this paper, perovskite (La 1-x Ag x ) 0.8 Ca 0,2 MnO 3 particle with different doped was synthesized by sol-gel processes. We study the effect of the sintering temperatures and time on the morphological of the samples. 2. Experimental The material (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3 has been prepared by sol-gel method where x=0 and x=0.5. Precursors were used including of La 2 O 3, AgNO 3, Ca(NO 3 ) 2.4H 2 O and Mn(NO 3 ) 2.4H 2 O. Each precursor was dissolved with nitric acid to obtain a transparent solution. Citric acid (C 6 H 8 O 7.H 2 O) with a mole ratio of citric acid 1:1.2 total metal ions. The ammonia solution is added to adjust the ph of the solution to 7. The resulting mixture is homogenized using 400 rpm magnetic stirrer and temperature at C to form a gel. The resulting gel was heated to 120 C in the oven for 3 hours to dry the sample to be gel highly viscous. After obtaining gel highly viscous, the sample was heated to a 500 C calcining temperature for 5 hours in the furnace for the decomposition of the organic precursor. Sintering temperature variations were done at 650 o C for 5 hours and 900 o C for 24 hours. Samples have characterization by using Scanning Electron Microscopy (SEM) and the composition of elements was examined by using X-ray Spectroscopy (EDX). 3. Result and Discussion Figure 1. SEM image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, Figure 2. SEM image of (La 1- x Ag x ) 0,8 Ca 0,2 MnO 3, (x = 0; T = 900 C, t = 24 h) (x = 0.5; T = 900 C, t = 24 h) 2

4 Figure 3. SEM image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, Figure 4. SEM image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, (x = 0; T = 650 C, t = 6 h) (x = 0.5; T = 650 C, t = 6 h) In Figure 1 until Figure 4, it is showed the SEM patterns of the (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3 when x=0 and x=0.5 at 900 C for duration of 24 h, samples were sintered at different temperatures and time duration. Figure 1 showed that the grain size of LCMO (x=0) were in the range nm with an average grain size of 78.4 nm. Figure 2 showed that the grain size of LACMO (x = 0.5) were in range nm with an average grain size of nm. It is found that the grain sizes are increased with increasing the Ag-doped. Meanwhile, at Figure 3 and Figure 4,.for the sample of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, when x=0 and x=0.5 at 650 C for duration of 5h, it is found that the samples are agglomerated because of short sintering time. The grain size growth by increase the sintering time, the grain have more time to grow up and poros can be released gradually [10]. Figure 5. EDX image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, Figure 6. EDX image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, (x = 0; T = 900 C, t = 24 h) (x = 0.5; T = 900 C, t = 24 h) 3

5 Figure 7. EDX image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, Figure 8. EDX image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, (x = 0; T = 650 C, t = 6 h) (x = 0.5; T = 650 C, t = 5 h) In Figure 5 until Figure 8 showed that there is no quantifiable loss of each elements. the composition of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3 ) are presented in Table 1. The composition almost same as a quantitative value between designated composition and measured composition, it happened because the EDX method is semi-quantitative analysis. Table 1. Compositional Analysis of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, a. (x = 0; T = 900 C, t = 24 h); b. (x = 0.5; T = 900 C, t = 24 h); c. (x = 0; T = 650 C, t = 6 h); d. (x = 0.5; T = 650 C, t = 6 h) Doping concentration Element Weight (%) Atomic (%) x = 0 La T = 900 o C Ag 0 0 t = 24 h Ca Mn O x = 0.5 La T = 900 o C Ag t = 24 h Ca Mn O x = 0 La T = 650 o C Ag 0 0 t = 6 h Ca Mn O x = 0.5 La T = 650 o C Ag t = 6 h Ca Mn O

6 Figure 5 until Figure 8 and Tabel 1 showed the chemical compositions and semi-quantitative EDX measurements. It is revealed that the cation atomic ratio of La: Ag: Ca: Mn is approaching to the nominal values in the composition of La 1-x Ag x Ca 0.2 MnO 3 [7]. Figure 9. BSE image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, Figure 10. BSE image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, (x = 0; T = 900 C, t = 24 h) (x = 0.5; T = 900 C, t = 24 h) Figure 11. BSE image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, Figure 12. BSE image of (La 1-x Ag x ) 0,8 Ca 0,2 MnO 3, (x = 0; T = 650 C, t = 6 h) (x = 0.5; T = 650 C, t = 6 h) Figure 9 until Figure 12 showed that the backscattered electron mode (BSE) of LACMO (x = 0 and x = 0.5) at 900 o C for duration of 24h are homogenous. LACMO (x = 0 and x = 0.5) at 650 o C for the duration of 5 h are agglomerated due to that some of Ag react with oxygen. They can be seen in silver color. Besides, we also found that there are perovskite phase and Ag.O phase at LACMO (x = 0 and x = 0.5) at 650 o C for the duration of 5 h. Summary (La 1-x Ag x ) 0.8 Ca 0.2 MnO 3 were synthesis by a sol-gel process. The samples were varied in temperature and time of sintering and doping variations of Ag x 0 and x 0.5. Sintering temperature variations were done 5

7 at 650 o C The SEM-EDX results show the characterization of samples depend on density, porosity, and granular morphology. Microstructures of perovskite materials have a better characterization at doping x 0.5 and at the highest temperature and sintering time.for 5 hours and 900 o C for 24 hours. The grain sizes are increased with increasing the Ag-doped and at the higher temperature and longer duration of sintering will make the nucleation processes in the sample better. Acknowledgment This work is financially supported by Universitas Indonesia under research grant Hibah PITTA (Hibah Publikasi Internasional Terindeks untuk Tugas Akhir Mahasiswa Universitas Indonesia with grant contract number is 634/UN2.R3.1/HKP.05.00/2017. The authors are also grateful to Department of Physics, Universitas Indonesia for research facilities. References [1] Smari M, Hamdi R, Dhahri E, Hlil E K, and Bessais L 2016 Correlation between magnetic and electric properties of La 0.5 Ca 0.3 Ag 0.2 MnO 3 based on critical behavior of resistivity Ceram. Int., vol. 42 no. 8 pp , [2] Kalyana Lakshmi Y and Reddy P V 2010 Influence of silver doping on the electrical and magnetic behavior of La 0.7 Ca 0.3 MnO 3 manganites Solid State Sci. vol. 12 no. 10 pp [3] Thanh T D, Linh D C, Manh T V, Phan T L, and Yu S C 2016 Magnetic and Magnetocaloric Properties of La 0.8-x Ag x Ca 0.2 MnO 3 Exhibiting the Crossover of First-and Second-Order Phase Transitions IEEE Trans. Magn. vol. 52 no.7 pp10 13 [4] Riahi K et al 2016 Effect of synthesis route on the structural, magnetic and magnetocaloric properties of La 0.78 Dy 0.02 Ca 0.2 MnO 3 manganite: A comparison between sol-gel, high-energy ball-milling and solid state process J. Alloys Compd. vol. 688 pp [5] Ye S L et al 2002 Effect of Ag substitution on the transport property and magnetoresistance of LaMnO 3 J. Magn. Magn. Mater. vol. 248 no.1 pp [6] Debnath J C and Strydom A M 2015 Large low field magneto-resistance and temperature coefficient of resistance in La 0.8 Ca 0.2 MnO 3 epitaxial thin film J. Alloys Compd. vol. 621 pp 7 11 [7] Xia W, Li L, Wu H, Xue P, and Zhu X 2017 Structural, morphological, and magnetic properties of sol-gel derived La 0.7 Ca 0.3 MnO 3 manganite nanoparticles Ceram. Int. vol. 43 no. 3 pp [8] Pekała M and Drozd V 2008 Magnetocaloric effect in nano- and polycrystalline La 0.8 Sr 0.2 MnO 3 manganites J. Non. Cryst. Solids vol. 354 no pp [9] Pekała M., Drozd V, Fagnard J F, and Vanderbemden P 2010 Magnetocaloric effect in nano- and polycrystalline manganites La 0.5 Ca0.5MnO 3 J. Alloys Compd. vol. 507 no. 2 pp [10] Ma J et al 2014 Enhancement of temperature coefficient of resistivity in La 0.67 Ca 0.33 MnO 3 polycrystalline ceramics Ceram. Int. vol. 40 no. 3 pp