Analysis of the microstructure of superconducting YBCO foams by means of AFM and EBSD

doi:10.1007/s40145-014-0123-z

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Abstract

YBa₂Cu₃O_y (YBCO) foam samples show an open, porous foam structure, which may have benefits for many applications of high-T_c superconductors. As the basic material of these foams is a pseudo-single crystalline material with the directional growth initiated by a seed crystal similar to standard melt-textured samples, the texture of YBCO is a very important parameter. Therefore, we analysed the local texture and grain orientation of the individual struts forming the foam by means of atomic force microscopy (AFM) and electron backscatter diffraction (EBSD). Due to the processing route starting with Y₂BaCuO₅ (211), a two-phase analysis must be performed, so a high surface quality is necessary to enable an automated EBSD scan. Good quality Kikuchi patterns were obtained from both the YBCO and 211 phases. We found an inhomogeneous distribution of the residual 211 particles, which are mainly randomly oriented and have sizes ranging between 200 nm and 15 μm. In contrast to this, the YBCO matrix shows a dominating orientation with cracks with a typical distance of 1–10 μm. Furthermore, the analysis of strut cross-sections reveals that the entire strut is converted to the YBCO phase.

Key words： high-T_c superconductors foam microstructure atomic force microscopy (AFM) electron backscatter diffraction (EBSD) orientation

Received: 12 June 2014 Published: 12 June 2015

Corresponding Authors: Michael Rudolf KOBLISCHKA

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	Articles by authors
	Michael Rudolf KOBLISCHKA
	Anjela KOBLISCHKA-VENEVA
	E. S. REDDY
	Gregor J. SCHMITZ

Cite this article:

Michael Rudolf KOBLISCHKA,Anjela KOBLISCHKA-VENEVA,E. S. REDDY, et al. Analysis of the microstructure of superconducting YBCO foams by means of AFM and EBSD[J]. Journal of Advanced Ceramics, 2014, 3(4): 317-325.

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http://jac.tsinghuajournals.com/EN/10.1007/s40145-014-0123-z OR http://jac.tsinghuajournals.com/EN/Y2014/V3/I4/317

(a) View of the entire foam piece, together with the fabric and the seed crystal. The arrows define the locations (1), (2) and (3) where struts were broken out for the investigations. (b) SEM image of the mounted foam struts for EBSD investigations under an angle of 70°. The yellow arrow points to the investigated strut cross-section.

AFM topography images of two locations on a foam strut. The sketch in (a) indicates the orientation of the strut with respect to the entire foam. The topography of image (a) shows a densely packed distribution of 211 particles embedded in the YBCO matrix. Clearly visible is the large amount of 211 particles on the sample surface. The particle size ranges between 1 μm and 10 μm. (b) presents a 211 particle free area due to particle pushing. The white arrows point to cracks filled with tiny 211 particles.

(a) AFM topography image of a foam strut and (b) 3D representation of the same data set. The sketch in (b) indicates the orientation of the strut with respect to the entire foam. Clearly visible is the large amount of 211 particles on the sample surface and the resulting height differences. The superconducting YBCO matrix is located below these 211 particles, which are much harder to be polished and form terraces. (c) and (d) give selected height profiles.

(a) and (b) AFM topography scans revealing details of the YBCO matrix; (c) and (d) the corresponding height profiles. The sketches in (a) and (b) indicate the orientation of the strut with respect to the entire foam. The blue arrows point to 211 particles embedded within the YBCO matrix.

(a) STM topography scan of an area close to a crack in the YBCO matrix. Here, a large number of 211 particles (blue arrows) embedded in the YBCO matrix get visible. (b) AFM topography image revealing details of the YBCO growth.

(a) EBSD phase map (YBCO red and Y-211 green) and (b) inverse pole figure map in [001]-direction obtained on a cross-section of a foam strut. The color code for the crystallographic orientations is given below the image for the YBCO and 211 phases. The orientation of the strut cross-section with respect to the original foam piece is indicated in the sketch below the map. RD (rolling direction) and TD (transverse direction) refer to the sample reference frame. The arrows in (b) point to misoriented YBCO grains due to the presence of the large 211 grains.

EBSD pole figures for (a) YBCO and (b) 211 phases in [001], [100], [110] and [010]-directions. For the 211 particles, pole figures of positions (1), (2) and (3) are shown. The representation of the intensities of both phases is normalized, enabling a direct comparison. Here, one can see that at positions (1) and (2) for YBCO and 211 only some dominating directions exist, while the 211 phase in position (3) is much more randomly oriented.

[1]	Reddy ES, Schmitz GJ. Superconducting foams. Supercond Sci Technol 2002, 15:L21-L24.
[2]	Reddy ES, Schmitz GJ. Ceramic foams. Am Ceram Soc Bull 2002, 81:35-37.
[3]	Noudem JG, Reddy ES, Schmitz GJ. Magnetic and transport properties of YBa2Cu3Oy superconductor foams. Physica C 2003, 390:286-290.
[4]	Reddy ES, Herweg M, Schmitz GJ. Processing of Y2BaCuO5 foams. Supercond Sci Technol 2003, 16:608-612.
[5]	Noudem JG, Guilmeau E, Chateigner D, et al. Properties of YBa2Cu3Oy-textured superconductor foams. Physica C 2004, 408–410:655-656.
[6]	Bartolomé E, Granados X, Puig T, et al. Critical state in superconducting single-crystalline YBa2Cu3O7 foams: Local versus long-range currents. Phys Rev B 2004, 70:144514.
[7]	Masson PJ, Brown GV, Soban DS, et al. HTS machines as enabling technology for all-electric airborne vehicles. Supercond Sci Technol 2007, 20:748-756.
[8]	Mitschang GW. Space applications and implications of high temperature superconductivity. IEEE T Appl Supercon 1995, 5:69-73.
[9]	Gu C, Zou S, Qu T, et al. Design of HTS coil for magnetic driving spacecraft. IEEE T Appl Supercon 2010, 20:997-1000.
[10]	Jung A, Diebels S, Koblischka-Veneva A, et al. Microstructural analysis of electrochemical coated open-cell metal foams by EBSD and nanoindentation. Adv Eng Mater 2014, 16:15-20.
[11]	Fiertek P, Andrzejewski B, Sadowski W. Synthesis and transport properties of porous superconducting ceramics of YBa2Cu3O7-δ. Rev Adv Mater Sci 2010, 23:52-56.
[12]	Noudem JG. Development of shaping textured YBaCuO superconductors. J Supercond Nov Magn 2011, 24:105-110.
[13]	Diko P, Kaňuchová M, Chaud X, et al. Oxygenation mechanism of TSMG YBCO bulk superconductor. J Phys: Conf Ser 2008, 97:012160.
[14]	Koblischka-Veneva A, Koblischka MR, Mücklich F, et al. Interactions of Y2BaCuO5 particles and the YBCO matrix within melt-textured YBCO samples studied by means of electron backscatter diffraction. Supercond Sci Technol 2005, 18:S158-S163.
[15]	Koblischka-Veneva A, Koblischka MR, Ogasawara K, et al. Interplay of YBCO and embedded 211 particles in melt-textured YBCO superconductors. J Supercond 2005, 18:469-474.
[16]	Guilmeau E, Lambert S, Chateigner D, et al. Quantitative texture analysis of polyphased oxides by diffraction: Example of Bi2223 sinter-forged cearmic and Y123 foam superconductors. Mat Sci Eng B 2003, 104:107-112.
[17]	Chateigner D, Wenk H-R, Pernet M. Orientation analysis of bulk YBCO from incomplete neutron diffraction data. J Appl Cryst 1997, 30:43-48.
[18]	Humphreys FJ. Characterisation of fine-scale microstructures by electron backscatter diffraction (EBSD). Scripta Mater 2004, 51:771-776.
[19]	Koblischka-Veneva A, Mücklich F, Koblischka MR, et al. Crystallographic orientation of Y2Ba4CuMOx (M = Nb, Zr, Ag) nanoparticles embedded in bulk, melt-textured YBCO studied by EBSD. J Am Ceram Soc 2007, 90:2582-2588.
[20]	Struers. Metalog guide. Available at .
[21]	Koblischka-Veneva A, Koblischka MR. Surface preparation of high-Tc superconductors for MO imaging. In Magneto-Optical Imaging. Johansen TH, Shantsev DV, Eds. Dordrecht:Kluwer Acad Press, 2004: 242-246.
[22]	Koblischka MR, Winter M, Hu A, et al. Stripe and criss-cross patterns in high-Tc superconductors revealed by atomic force microscopy and scanning tunnelling microscopy. Jpn J Appl Phys 2006, 45:2259-2263.
[23]	Winter M, Koblischka MR, Koblischka-Veneva A, et al. Nano-stripe structures in light rare-earth high-Tc superconductors. J Phys: Conf Ser 2007, 61:601-605.
[24]	TexSEM Laboratories (TSL). Orientation imaging microscopy software version V4.0, user manual. TexSEM Laboratories (TSL), Draper, UT, USA.
[25]	Koblischka-Veneva A, Koblischka MR, Simon P, et al. Electron backscatter diffraction study of polycrystalline YBa2Cu3O7-δ ceramics. Physica C 2002, 382:311-322.
[26]	Koblischka MR, Koblischka-Veneva A. Applications of the electron backscatter diffraction technique to ceramic materials. Phase Transit 2013, 86:651-660.
[27]	Grossin D, Henrist C, Mathieu J-Ph, et al. EBSD study on YBCO textured bulk samples: Correlation between crystal growth and 'microtexture'. Supercond Sci Technol 2006, 19:190-199.
[28]	Jirsa M, Zablotskii V, Petrenko P, et al. Vortex interaction with large particles in bulk RE-123 compounds. J Low Temp Phys 2005, 139:103-109.
[29]	Obradors X, Yu R, Sandiumenge F, et al. Directional solidification of REBa2Cu3O7 (RE = Y, Nd): Microstructure and superconducting properties. Supercond Sci Technol 1997, 10:884-890.
[30]	Horcas I, Fernández R, Gómez-Rodríguez JM, et al. WSXM: A software for scanning probe microscopy and a tool for nanotechnology. Rev Sci Instrum 2007, 78:013705.