# Optical Analysis of Ho 3+ Ions Doped BaGd2Ti4O12 Ceramics

B Munisudhakar, C Nageswara Raju, P Sreenivasulu Reddy, S Hemasundara Raju

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B Munisudhakar, C Nageswara Raju, P Sreenivasulu Reddy, S Hemasundara Raju. Optical Analysis of Ho 3+ Ions Doped BaGd2Ti4O12 Ceramics. Mechanics, Materials Science & Engineering MMSE Journal. Open Access, 2017, 9, 10.2412/mmse.84.39.432. [hal-01499561](https://hal.science/hal-01499561)

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Optical Analysis of Ho³⁺ Ions Doped BaGd₂Ti₄O₁₂ Ceramics

B. Munisudhakar¹, C. Nageswara Raju², P. Sreenivasulu Reddy³, S. Hemasundara Raju³, a

1 – Department of H&S, SV College of Engineering, Tirupati, India

3 – Department of Physics, Sri Venkateswara Degree College, Kadapa, India

2 – Department of H&S, SV College of Engineering, Kadapa, India

a – hemaredi_raju2010@yahoo.com

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DOI 10.2412/mmse.84.39.432 provided by [Seo4U.link](https://seo4U.link)

**Keywords:** XRD, SEM, emission, excitation.

**ABSTRACT.** Ho³⁺ (5 mol %) ions doped Barium Gadolinium Titanate (BaGd₂Ti₄O₁₂) powder ceramics were synthesized by solid state reaction method. From the X-ray diffraction profiles it is observed that the prepared ceramics were crystallized in the form of orthorhombic structure. Agglomeration and the nanometer particle size were observed from the SEM images of the ceramics. The emission spectrum Ho³⁺: BaGd₂Ti₄O₁₂ powder ceramics has shown *blue* emission at 467 nm (⁵F₃ → ⁵I₈) with an excitation wavelength 208 nm.

**Introduction.** One of the most important electro ceramics is barium titanate. Barium titanate is a good dielectric material with a high dielectric constant and it is a ferroelectric, piezoelectric and pyroelectric with good nonlinear optical properties. Barium titanate compound is an electrical insulator because of its energy and it has been used for a wide range of scientific and industrial applications such as capacitors, ultrasonic transducers, piezoelectric sensors, Barium titanate ceramics applications in various fields such as optical limiting, switches, flat panel displays, modulated-type optical devices and second harmonic generation. Rare-earth ions doped titanate based phosphors have attracted significant importance for potential applications in white-light emitting diodes [1]. Gadolinium compounds doped with rare earth ions are used as the red phosphors for the preparation of WLEDs and gadolinium containing host lattices are also used for making green phosphors for colour TV tubes. From the literature, it is observed that many authors have been reported on PL analysis of titanate based systems such as gadolinium titanate, zirconium titanate, compounds can find potential applications in optoelectronic devices [2]. Rare earth ions doped ceramic hosts have a wide range of applications in the fields of lamp phosphors, solid state lighting in display devices, white light generation [3]. So for no reports have been made on the photoluminescence property of thulium doped barium gadolinium titanate (BaGd₂Ti₄O₁₂) ceramics. In this paper, we report on the synthesis, XRD, SEM and PL analysis of Ho³⁺ ions doped BaGd₂Ti₄O₁₂ ceramics for novel applications.

**Experimental studies.** BaGd₂-xTi₄O₁₂: REₓ³⁺ (RE = Ho and x = 5 mol %) ceramics were prepared by solid state reaction method. The starting chemicals used for the preparation of these ceramics were purchased from the Sigma Aldrich with 99.9 % purity and the chemicals purchased were used as received without any further purification. The starting materials such as BaCO₃, Gd₂O₃, TiO₂ and Ho₂O₃ were taken in an appropriate stoichiometric ratio. Then, these powders were grounded thoroughly in an agate mortar and the mixtures were put into alumina crucibles. They were heated in
an electric furnace at a temperature 1000°C for 2h. The final samples were white powders and then used for the characterization.

Structural characterization of these samples has been carried out from the X ray powder diffraction measurements on a XRD 3003 TT Seifert diffractometer with CuKα radiation (λ=1.5406Å°) at 40 kV and 20 mA and the 2θ range was varied between 10° and 80°. Morphology of the ceramic powder was examined on a ZEISS-EVO-MA15 ESEM. The scanning electron microscopy (SEM) image was obtained for samples by using a 35mm camera attached to a high resolution recording system. Both the excitation and emission spectra were obtained on a SPEX Fluorolog-2 Fluorimeter (Model II) with data max software to acquire the data with a Xe-arc lamp (150 W) as the excitation source.

## Results and Discussion

**XRD analysis.** Fig. 1. shows the XRD profile of 5 mol% of Ho³⁺: BaGd₂Ti₄O₁₂ ceramics, from the XRD profiles, it is observed that these powder ceramics are having the orthorhombic structure (using the software namely JCPDS No: 43-0233) having diffraction peaks which are consistent. The rare earth ions Ho³⁺: doped BaGd₂Ti₄O₁₂ ceramic does not influence the crystal structure.

<figure><img src="image_3.png" /><figcaption>Fig. 1. XRD profile of 5 mol% of Ho³⁺: BaGd₂Ti₄O₁₂ ceramics.</figcaption></figure>

**SEM analysis.** Fig. 2 shows SEM micrograph of the 5 mol% of Ho³⁺: BaGd₂Ti₄O₁₂ ceramic powder, from this image shows that the particles are agglomerated with various shapes and sizes and the average grain size is around at ~200 nm.
<figure><img src="image_4.png" /><figcaption>Fig. 2. SEM image of Ho³⁺: BaGd₂Ti₄O₁₂ ceramics.</figcaption></figure>

<figure><img src="image_5.png" /><figcaption>Fig. 3. Excitation spectrum of 5 mol% of Ho³⁺: BaGd₂Ti₄O₁₂ ceramics.</figcaption></figure>

**Ho³⁺: BaGd₂Ti₄O₁₂ ceramics.** Fig.3 shows the excitation spectrum of 5 mol % Ho³⁺: BaGd₂Ti₄O₁₂ powder ceramics, from this spectrum the excitation wavelengths at 208 nm and 249 nm corresponding to the transitions ⁵I₈→ ³F₃, ⁵I₈→ ³D₃ respectively. Among these transitions the transition at ⁵I₈→ ³F₃ is most intense transition compared to other one and has been selected for the measurement of emission spectrum of Ho³⁺: Ba₃Y₂WO₉ powder ceramics. The emission spectrum of 5 mol % Ho³⁺: BaGd₂Ti₄O₁₂ powder ceramics is shown in Fig.4. From the emission spectrum, the wavelengths at 467 nm, 560 nm, 606 nm and 628 nm corresponding to the transitions ⁵F₃→ ⁵I₈, ⁵S₂+ ⁵F₄→ ⁵I₈, ⁵F₅→ ⁵I₈ and ⁵F₅→ ⁵I₈ respectively. Among these the transition ⁵F₃→ ⁵I₈ is most intense compared to others and is the characteristic of *blue* emission. From the emission spectra Ho³⁺: BaGd₂Ti₄O₁₂ powder ceramics shows tricolor emissions at blue (465 nm), green (558 nm) and red (609 nm). Assignments to these bands have been made by the previously published articles [24]. Among these transitions the transition at ⁵S₂→ ⁵I₈ is more efficient for laser action.
<figure><img src="image_6.png" /><figcaption>Fig. 4. Emission spectrum of 5 mol% of Ho³⁺: BaGd₂Ti₄O₁₂ ceramics.</figcaption></figure>

**Summary.** It is concluded that, 5 mol % of Ho³⁺: BaGd₂Ti₄O₁₂ powder ceramics have been synthesized by using a solid state reaction method. The XRD profile indicates the tetragonal phase structure of the prepared ceramics. The emission spectrum of Ho³⁺: BaGd₂Ti₄O₁₂ powder ceramics have shown an intense blue emission at 467 nm with the excitation wavelength λexc = 208 nm. These powder ceramics may be used as novel luminescent materials in various optical systems.

References

[1] Parveen Kumar, Sangeeta Singh, Manjula Spah, J.K. Juneja, Chandra Prakash and K.K.Raina Synthesis and dielectric properties of substituted barium titanate Ceramics. J. Alloy. Compd. 489, 59-63 (2010).

[2] Sheela Devi and A.K. Jha Structural, Dielectric and Ferroelectric properties of Tungsten substituted Barium Titanate ceramics. Asian J. Chem. 21, S117-124 (2009).

[3] K.V.Syamala, G. Panneerselvam, G.G.S. Subramanian and M.P. Antony Synthesis, characterization and thermal expansion studies on europium titanate (Eu₂TiO₅). Thermochim Acta 475, 76-99 (2008).

[4] V. Lojpur, M. Nikolic, L. Mencic, O. Milosevic, M.D. Dramicanin Y₂O₃: Yb, Tm and Y₂O₃: Yb, Ho powders for low-temperature thermometry based on up-conversion fluorescence. Ceramics international 39-2, 1129-1134 (2013).

[5] C. Joshi, Y. Dwivedi and S.B. Rai Structural and optical properties of Ho₂TeO₆ micro-crystals embedded in tellurite matrix. Ceramics international 37 (2011) 2603-2608.

[6] Zhao Junfeng, Chen Xi, Rong Chunying, Yu Liping, Lian Shixun “A tunable yellow emission from three-band emission of singly doped single-phased phosphor BaY₂S₄:Ho³⁺”. J. Rare Earths 29 (2011) 436.

Cite the paper

B. Munisudhakar, C. Nageswara Raju, P. Sreenivasulu Reddy, S. Hemasundara Raju (2017). *Optical Analysis of Ho³⁺ Ions Doped BaGd₂Ti₄O₁₂ Ceramics*. *Mechanics, Materials Science & Engineering*, Vol 9.
doi:10.2412/mmse.84.39.432