Structure,Rietveld Refinement Study of BaCoxTixFe12-2xO19 ferrite Using Powder XRD Analysis Farouq I. Hussain Qader Dept.of Physics/ College of Education For Pure Science (Ibn-Al-Haithm) University of Baghdad Received in: 4 April 2013 Accepted in : 24 June 2013 Abstract BaCoxTixFe12-2xO19 (x=0.1, 0.5, 0.7, 0.9, 1.7) were prepared using powder technology technique . X-ray diffraction with diffractometer CuKα radiation analysis and Rietveld refinement of the samples were studied and showed a single phase of hexagonal structure with SP63/mmc space group . Lattice parameters, cell volume , crystallite size and x-ray density were determined .The hexagonal structure was represented by using PowderCell program showing the atomic positions of Co ,Ti, and Fe ions. Keywords: M-type hexaferrite-XRD analysis-Rietveld refinement 70 | Physics @a@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@Ü‹127@@ÖÜ»€a@I2@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (2) 2014 Introduction Barium hexaferrite with a chemical formula BaCoxTixFe12-2x O19 is one of the most important compositions for perpendicular magnetic recording due to its large saturation magnetization; and good stability [1] .M-type barium hexa-ferrite has been investigated as a material for microwave absorber devices and also in various applications [2]. Because of the industrial relevance of barium hexa-ferrite ,scientific interest ,they have been extensively studied because of their large intrinsic uniaxial anisotropy and high coercively ,which make them widely used in various applications [3].In order to reduce the anisotropy field which causes poor overwrite modulation[1-5] and satisfy the desired applications many studies were taken out to modify the magnetic properties of barium hexaferrite by the substitution of the Fe3+ ion with cations such as (Sn4+, Ni2+ ,Co2+ ,Co3+ Ti4+…..) [1-5] .The structure of M-type barium hexaferrite with the formula BaCoxTixFe12-2xO19 has been studied in the present work using powder x-ray diffraction analysis technique and we have investigated the advantages of this technique to study and measure the most important features and properties of our ferrite [4-15] such as the average grain size ,x-ray density ,lattice parameters of the unit cell and the cell volume of samples and the atomic positions sites in the lattice structure[6-15].The structure of the M-type barium ferrite (BaFe12O19) with space group SP63/mmc is symbolically described (RSR*S*)where R is three layers block (two O4 containing one BaO3) with composition Ba2+Fe62+O11)2- and S is two layers O4-layer block with compositions ( Fe63+O8)2+ when the asterisk means that the corresponding block has been turned 180° around the c-axis.In this structure the metallic cations are distributed within three different kinds of octahedral sites (2a , 4fVI , and 12K sub lattice) ,one tetrahedral site (4fVI sub lattice ) and one pseudo tetrahedral site (4e(1/2) sub lattice as shown below:- [8,9] Spin direction No. of ions/Fu Block coordination Sub lattice cations Up 1 S octahedral 2a M1 Up 1 R Pseudo-tetrahedral 4e(1/2) M2 Down 2 S Tetrahedral 4fIV M3 Down 2 R octahedral 4fIV M4 up 6 R-S octahedral 12K M5 71 | Physics @a@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@Ü‹127@@ÖÜ»€a@I2@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (2) 2014 In this work we report the intrinsic structure of the classical BaCoxTixFe12-2x 1O19 doping scheme. Experimental procedures The synthesis of polycrystalline BaCoxTixFe12-2xO19 samples (x=0.1 0.5 ,0.7 ,0.9 ,1.7)were prepared by powder technology method with different sintering temperatures listed in Tab.1 . X-ray diffraction analysis was carried out using SHIMADZU6000 diffractometer with CuKα radiation. The obtained XRD data was compared with standard pattern of JCPDS-ICDD (International Center for Diffraction Data).Powder diffraction (PXRD) is a technique used to characterize the crystal structure, grain size, volume, x-ray density and lattice parameters and used to identify unknown substances by comparing diffraction data by the (ICDD) [10-15]. First we calculated the lattice parameters using the well-known relation bellow:-[10] For hexagonal structure a=b≠ c, α=β=90° γ=120° 𝟏 𝒅𝒉𝒌𝒍 𝟐 = 𝟒 𝟑 (𝒉 𝟐 𝒂𝟐 + 𝒉𝒌 𝒂𝟐 + 𝑲 𝟐 𝒂𝟐 )𝒍 𝟐 𝒄𝟐 …….(1) Volume of hexagonal unit cell: V=(√𝟑 𝟐 ) a2c=0.886 a2c……( 2) x-ray density for hexagonal structure is:- x-ray= Z.M / V.NA ………(3)ρ M=molecular weight , V=x-ray volume , Z=2 for hexa-unitcell , NA=Avogadro number And to calculate the crystallite grain size we used scherrer 's equation from the diffraction peaks broadening. D=0.94.λ / β.cosθ ……..(4) Where: - β=FWHM in radiant , D=polycrystalline grain size(nm) Λ forCuKα =0.154059 (nm) , θ=Brag angle. wavelength Porosity ratio for the prepared samples was calculated using the relation:- P= 1- (ρbulk/ρx-ray) ……….(5) Where ρbulk=mass/volume (gram/Cm2). Rietveld analysis:- Rietveld refinement data of all the prepared hexa-ferrite carried out by using the Fullprof and UnitCell programs and studied very carefully and from Rietveld refinement data we calculated the atomic positions of our samples (x,y,z) and exihibited the structure of our hexagonal M-type barium ferrite doped with Co-Ti using the PowderCell program. Results and Discussion Fig.1 shows XRD patterns of Co-Ti doped barium hexa-ferrite (BaCoxTixFe12-2xO19) with different concentrations ,comparing with the standard pattern of (BaFe12O19) with space group SP63/mmc (JCPDS file no. 043-0002)all the XRD patterns have been indexed (hkl) manually and by using equations (1-5) we calculated lattice parameters, x-ray cell volume and x-ray density .Table.1 summarizes the composition dependence of lattice parameters determined by x-ray diffraction analysis . All the patterns showed single phase hexagonal structure with SP63/mmc and from these data we may propose that the lattice parameter (c-values) increases due to greater ionic radii of Co-Ti than the ionic radius of iron ions (~0.55 A°) and the average crystallite size decreases with doped barium ferrite (Co- Ti).The Rietveld refinement data is shown in Fig.2 and the refined lattice parameters are summarized in Table.2. Fig.3 shows the hexagonal structure representation and the atomic positions (xyz) by using data information from the refinement file and PowderCell programs. The samples possess a hexagonal structure SP63/mmc with two molecules in unit cell (z-z). 72 | Physics @a@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@Ü‹127@@ÖÜ»€a@I2@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (2) 2014 Conclusions BaCoxTixFe12-2xO19 (x=0.1, 0.5, 0.7, 0.9, 1.7) were synthesized by powder technology technique. The x-ray diffraction analysis and Rietveld refinement for all the prepared samples revealed existence of single phase identified by JCPDS file no. hexagonal phase with space group SP63/mmc in agreement with the data reported in most scientific researches. We also showed that XRD analysis is a very powerful tools in material science and technology researches. References 1- Ibrahim Bsoul,(2009) , preparation of nano crystalline BaCoxTixFe12-2xO19 by ball milling method and there magnetic properties ,Jordan Journal of physics 2 (2): 95- 102. 2- Aylin Gurbus , Nurhan Onar , Ismail Ozdemer , Abdullah Cahit Karaoglani and Erdal Celik ( 2012) ,Structural , Thermal and Magnetic properties of barium – ferrite powders substituted with Mn, Cu, or Co and X( X= Sr and Ni) prepared by sol-gel method , Material and Technology 46 (3):305 – 310. 3-. Williams, J. M.; Adetunji, J. and Gregori, M. (2000), Mӧssbauer spectroscopic determination of Fe3+and Co2+ in substituted barium hexaferrite Ba(CoTi)xFe12-2xO19 Journal of magnetism and magnetic materials ,220,124-128. 4- Taiki Nakanishi , Maki Okube , Takeshi Toyoda , Akiko Nakao and Satoshi Sasaki,(2008), Site occupancy in BaTiMnFe10O19 hexa-ferrite , Photon Factory Activity Report2007 # 25 part B 5- Ashima, Sujata Sanghi , Ashish Agarwal, Reety, (2012) Rietveld refinement , electrical properties and magnetic characteristics of Ca- Sr substituted barium hexaferrite, Journal of alloys and compounds( 513),436-444. 6- Bahadur D., Fischer W.and Rane M. V. (2012) , In- situ high temperature X-ray diffraction studies of non-stoichiometric Ni-Zr substituted barium hexagonal ferrites prepared by citrate precursor route , Internet articals 7- Gairola ,S. P. ; Vivek Verma, Singh A. ; Purohit ,L P.and. Kotnala, R. K.(2009) ,Modified composition of barium ferrite to act as microwave absorber in X-band frequencies , Solid state communications. Article in press. 8- Batlle X. , Obradors X., Rodrriguez J., Pernet M. , Cabanas M. V. and Vallet M. (1991) " Cation distribution and intrinsic magnetic properties of Co-Ti doped M- type barium ferrite" J. Appl. Phys. 70(3), 1. 9-Ramachandran, B.(2010) , Structural , Optical ,Electrical , Magnetic and Magneto electric properties of undoped and doped polycrystalline Bismuth ferrite, PhD Thesis , Department of Physics , Indian Institute of Technology , MADRAS. 10- Christopher Hammond(2009) The Basic Of Crystallography and Diffraction, 3rd edition , International union of Crystallography . Oxford science puplicatio. 11- Katerina Seleznera E. (2008) Magnetoelectric composites based on hexagonal ferrite universidade de Aveiro Departamento de Engenharia ceramica edovidro. 12-Salvi S. V. & Joshi V.H. (2009) Effect of dopants on barium hexaferrite , Indian Journal Of pure & Applied Physics.(47). 277- 281. 13- Ravinder, D.; Mahesh, P. ;Koteswara Rao, K.; Vitha,l M. and Boyanov, B. S. (2004) Electrical conductivity of Ba- Co- Ti – hexagonal ferrite " Journal of Alloys and compounds. 364) ,17-22.( 14- The, G.B.and Saravanan, N. and Jefferson, D. A.(2007), A study of Manetoplumbite – type (M- type ) Cobalt- Titanium – substituted barium ferrite BaCoxTixFe12-2xO19 (x=1- 6), Materials Chemistry and physics . (105),253- 259. 15- Bsoul, I. and. Mahmood, S. H,(2009), Structural and Magnetic properties of BaFe12- xAlxO19 , prepared by Milling and Calcination , Jordan Journal Of Physics. 2(.3), 171 – 179. 73 | Physics @a@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@Ü‹127@@ÖÜ»€a@I2@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (2) 2014 Table No(1): lattice parameters and average crystallite size with x-ray volume and density of BaCoxTixFe12-2xO19 measured by XRD. sample x BaC0xTixFe12-2xO19 T sintering℃ a=b A0 C A0 C/a ρx-ray gm/cm 3 Dnm Vol. of the cell x1024 Cm3 B1 0.1 BaCo0.1 Ti0.1Fe11.8O19 1450 5.89 23.21 3.94 5.091 52 697.306 B2 0.5 BaCo0.5 Ti0.5Fe11 O19 1250 5.9 23.27 3.94 5.24 58.17 701.4848 B3 0.7 BaCo0.7 Ti0.7Fe10.6O19 1350 5.89 23.28 3.952 5.25 52 699.409 B4 0.9 BaCo0.9 Ti0.9Fe10.2O19 1450 5.89 23.3 3.95 5.091 42 720.94682 B5 1.7 BaCo1.7 Ti1.7Fe8.6O19 1450 5.9 23.16 3.92 5.23 42.822 699.1688 Table No( 2): lattice parameters of prepared samples after refinements using Fullprof programs Space group (gm/cm2)ρ C (A°) a =b (A°) samples P63/mmc 5.092 23.176 5.883 B1 P63/mmc 5.124 23.186 5.886 B2 P63/mmc 5.25 23.213 5.887 B3 P63/mmc 5.12 23.231 5.889 B4 P63/mmc 5.23 23.321 5.891 B5 Figure No(1): XRD patterns of BaC0xTixFe12-2xO19 with different dopant concentrations 74 | Physics @a@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@Ü‹127@@ÖÜ»€a@I2@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (2) 2014 Figure No(2): the Rietveld refinement data of prepared sample B10 by Fullprof program 75 | Physics @a@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@Ü‹127@@ÖÜ»€a@I2@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (2) 2014 Figure No.(3): structure representation for barium hexa-ferrite doped with Co-Ti by using PowderCell programs 76 | Physics @a@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@Ü‹127@@ÖÜ»€a@I2@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (2) 2014 -BaCoxTixFe12دراسة تركیب وتصفیة ریتفیلد للفیرایت السداسي بصیغة 2xO19 ) باستخدام تحلیل حیود االشعة السینیةPXRD( قادر فاروق ابراھیم حسین التربیة للعلوم الصرفة ابن الھیثم، جامعة بغدادقسم الفیزیاء، كلیة 2013حزیران 24قبل البحث 2013نیسان 4استلم البحث في: الخالصة باستخدام تقنیة تكنولوجیا المساحیق وبنسب تطعیم BaCoxTixFe12-2xO19تم تحضیر الفیرایت ذو الصیغة الكیمیائیة فحوصات حیود االشعة السینیة وممقارنتھا مع واجریت) x=0.1 0.5 ,0.7 ,0.9 ,1.7( الكوبلت والتیتانیوم مختلفة لكل من االبعاد وقیست) واظھرت جمیع النماذج طور سداسي واحد ICDDالتابعة للمركز الدولي لبیانات الحیود ( JCPDSملفات االشعة السینیة لھا والمعادالت الخاصة بھذا فة باستخدام تحلیل ) وكذلك الحجم الحبیبي والكثاa=b , c, c/aالبلوریة لھا ( واعادة القیاسات باستخدام تصفیة ریتفیلد ودراسة المواقع للذرات في شبیكة الباریوم فیرایت المطعم بالكوبلت ، التحلیل .PowderCellو Fullprofوالتیتانیوم ورسم الشبیكة باستخدام البرامج الحاسوبیة باریوم فیرایت السداسي –تصفیة ریتفیلد –االشعة السینیة حیود -: الكلمات المفتاحیة 77 | Physics @a@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ÚÓ‘Ój�n€a@Î@Úœäñ€a@‚Ï‹»‹€@·rÓ:a@Âig@Ú‹©@Ü‹127@@ÖÜ»€a@I2@‚b«@H2014 Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (2) 2014