The abbreviation HKZ (Hochdruck-Kristallzüchtungsanlage) stands for a unique high-pressure optical floating zone crystal growth furnace. It features a vertical 2-mirror setup with a highly homogeneous and to a great extent controllable light power distribution on the crystal rod. One of the key characteristics of the furnace is the ability to work at pressures of up to 300 bar with different gases and mixtures in the growth chamber.

Additionally, individual gas flow rates can be adjusted and controlled freely and independently over the complete pressure range.Using powerful xenon short arc lamps, melting temperatures over 3000 °C can be achieved. While the light power tuning range of arc lamps is limited, the thermal energy in the growth chamber is step-less adjustable between 0 and 100 % thanks to a power shutter system in the light.

Highly precise magnetically coupled linear and rotation feed through systems with pulling rates starting from 0.1 mm/h, advanced process monitoring technologies and a comfortable PLC user interface guarantee extensive control of the growth process. The temperature of feed rod, melt zone and crystal is measured directly via a patented in-situ temperature measurement system. An optional after-heater is applicable with all possible atmospheres and pressures—also with high-pressure oxygen atmospheres.

This worldwide unique setup allows the user to rule the growth of materials, which are difficult or impossible to handle at low due to the higher volatility or higher partial pressure of their elements. A very important characteristic is the highly developable and easily expandable, modular design of the HKZ furnace system, which allows add-ons and upgrades to all of current furnaces in an easy and cost-efficient way.

• Argon and oxygen (pure and in any mixture ratio)
• Many other gases possible on request
• Pressure: up to 300 bar (different version available: 10 bar, 50 bar, 150 bar, 300 bar)
• Turbulence suppression system
• PLC controlled gas flow: 0.25 l/min to 1 l/min, individually adjustable for different gases
• Vacuum: down to 1*10^-5 mbar
• Turbo pump close to the process chamber, wide diameter connections
• UHV system possible on request
• Active titanium getter gas cleaning (removes O₂ traces in argon down to 10^-12 ppm, applicable under high-pressure conditions)
• Oxygen content measurement system

• Highly transparent material
• Pressure-proved between 0 and 300 bar (or the max. pressure depending on the version)
• Long life span due to protective tube
• Sample holder for 6,8 mm or 9,8 mm samples

• Xenon short arc lamp, different kinds available between 3 kW and 15 kW
• Temperature: up to 3000 °C
• Lamp power control
• Power shutter in the light beam, step-less adjustable between 0 and 100 %
• Precise motor-driven lamp positioning unit, workable during the experiment
• Upper and lower optimized elliptical mirrors, aluminum or gold coated
• Mirror position adjustment system

• Precise magnetically coupled linear and rotation feed through system
• Pulling rate: 0.1 mm/h to 200 mm/h (lower pulling rates possible on request)
• Fast service gear (approx. 0.6 mm/s )
• Pulling length: 195 mm
• Rotation rate: 0 to 70 rpm

• Two-color pyrometer with a patented stroboscopic measurement method
• Adjustable time interval
• Adjustable position
• Several temperature ranges

• Versatile and modular unit
• Applicable with all possible atmospheres and pressures
• Easily exchangeable heater coils
• Highly adaptable to special needs

• High-resolution CCD camera with specialized lenses and filters
• Monitoring application: visual control, video recordings, snapshots and length measurements during the growth process
• Power ramp and traveling ramp functions
• Front window for direct observation of the growth chamber
• All system parameters are comfortably controllable and adjustable via a PLC-based software application with two 27" touch screens
• Safety system with protection housing, door lock system, automatic shut down function

• Gas supply with the intended pressure
• Exhaust air system
• Energy supply: 3-phase AC, 50 Hz, 400 V, 63 A
• Cooling water

• Height: 3020 mm , width: 1631 mm, depth: 920 mm

• Dr. Hugo Schlich, MaTecK GmbH
• Dr. A. C. Komarek, Prof. Dr. Liu Hao Tjeng, MPI CPfS Dresden
• Dr. Jiaqiang Yan, Dr. Brian Sales, Oak Ridge National Laboratory
• Dr. Jennifer Zheng, Dr. John F. Mitchell, Argonne National Laboratory
• Dr. Qisi Wang, Prof. Dr. Jun Zhao, Fudan University Shanghai

• Feng, H., Huang, S., Yu, H., Zheng, J., Liu, C., Yang, X., Yang, F. (2022). Concentration and temperature dependence behaviors of photoluminescence and scintillation properties of Lu₂O₃:Pr single crystals. Journal of Alloys and Compounds, 903, 163884.

• Guo, H., Zhao, L., Baenitz, M., Fabrèges, X., Gukasov, A., Melendez Sans, A., Khomskii, D., Tjeng, L. H., Komarek, A. C. (2021). Emergent 1/3 magnetization plateaus in pyroxene CoGeO₃. Physical Review B, 3, L032037.

• Zhang, P., Gao, M., Guo, R., Xu, J., Wang, Y., Luo, L. (2021). Structural and optical properties of GdAlO₃:Tb³⁺ crystal obtained by optical floating zone method. Optik, 239, 166880.

• Zhao, L., Hu, Z., Guo, H., Geibel, C., Lin, H.-J., Chen, C.-T., Khomskii, D., Tjeng, L. H., Komarek, A. C. (2021). Single Crystal Growth and Physical Properties of Pyroxene CoGeO₃. Crystals, 11(4), 378.

• Hergett, W., Neef, C., Meyer, H.-P., Klingeler, R. (2021). Challenges in the crystal growth of Li₂FeSiO₄. Journal of Crystal Growth, 556, 125995.

• Haihang, Y., Qianli, L., Changjiang, L., Wei, J., Xuechun, Y., Mei, Y., Rihua, M., He, F. (2021). Comparison of Photoluminescence and Scintillation Properties Between Lu₂O₃:Eu Single Crystal and Transparent Ceramic. IEEE Transactions on Nuclear Science, 68, 4.

• Gao, M., Zhang, P., Luo, L., Guo, R., Wang, Y. (2021). Structural and optical characterization of Gd₂SiO₅:Tb³⁺ crystal obtained by optical floating zone method. Optik, 225, 165814.

• Tay, D., Shang, T., Puphal, P., Pomjakushina, E., Ott, H.-R., Shiroka, T. (2020). Unusual ²⁷Al NMR shift in the Weyl-fermion systems LaAlGe and PrAlGe. Physical Review B, 102, 241109.

• Upton, M. H., Zhang, J., Zheng, H., Said, A., Mitchell, J. F. (2020). Electronic coupling in square planar La₄Ni₃O₈. Journal of Physics: Condensed Matter, 32, 42.

• Guo, H., Li, Z. W., Chang, C. F., Hu, Z., Kuo, C.-Y., Perring, T. G., Schmidt, W., Piovano, A., Schmalzl, K., Walker, H. C., Lin, H. J., Chen, C. T., Blanco-Canosa, S., Schlappe, J., Schüßler-Langeheine, C., Hansmann, P., Khomskii, D. I., Tjeng, L. H., Komarek, A. C. (2020). Charge disproportionation and nano phase separation in RSrNiO₄. Scientific Reports, 10, 18012.

• Zhang, J., Zheng, H., Chen, Y.-S., Ren, Y., Yonemura, M., Huq, A., Mitchell, J. F. (2020). High oxygen pressure floating zone growth and crystal structure of the metallic nickelates R₄Ni₃O₁₀ (R=La, Pr). Physical Review Materials, 4, 083402.

• Zheng, H., Wang, B.-X., Phelan, D., Zhang, J., Ren, Y., Krogstad, M. J., Rosenkranz, S., Osborn, R., Mitchell, J. F. (2020). Oxygen Inhomogeneity and Reversibility in Single Crystal LaNiO_3−δ. Crystals 10(7), 557.

• Dey, K., Sauerland, S., Werner, J., Skourski, Y., Abdel-Hafiez, M., Bag, R., Singh, S., Klingeler, R. (2020). Magnetic phase diagram and magnetoelastic coupling of NiTiO₃. Physical Review B, 101, 195122.

• Lee, J.-E., Burkhardt, U., Komarek, A. C. (2020). Synthesis of a New Ruthenate Ba₂₆Ru₁₂O₅₇. Crystals, 10(5), 355.

• Zhang, J., Phelan, D.  Botana, A. S.,  Chen, Y.-S., Zheng, H., Krogstad, M., Wang, S. G., Qiu, Y., Rodriguez-Rivera, J. A., Osborn, R., Rosenkranz, S., Norman, M. R., Mitchell, J. F. (2020). Intertwined density waves in a metallic nickelate. Nature Communications, 11, 6003.

• Huangfu, S., Jakub, G. D., Zhang, X., Blacque, O., Puphal, P., Pomjakushina, E., von Rohr, E. O., Schilling, A. (2020). Anisotropic character of the metal-to-metal transition in Pr₄Ni₃O₁₀. Physical Review B, 101, 104104.

• Haihang, Y., Changjiang, L., Zhikun, Z., Shimin, H., Yunling, Y., Rihua, M., He, F., Jingtai, Z. (2020). Single crystal growth and luminescent properties of YSH:Eu scintillator by optical floating zone method. Chemical Physics Letters, 738, 136916.

• Pejchal, J., Guguschev, C., Schulze, M., Jary, V., Mihokova, E., Rubesova, K., Jakes, V., Barta, J., Nikl, M. (2019). Luminescence and scintillation properties of strontium hafnate and strontium zirconate single crystals. Optical Materials, 98, 109494.

• Liu, F., Xu, C., Shen, S., Li, N., Guo, H., Lü, X., Xiang, H., Bellaiche, L., Zhao, J., Yin, L., Yang, W., Wang, W., Shen, J. (2019). Pressure-induced large enhancement of Néel temperature and electric polarization in the hexagonal multiferroic Lu_0.5Sc_0.5FeO₃. Phys. Rev. B, 100, 214408.

• Dey, K., Hergett, W., Telang, P., Abdel-Hafiez, M. M., Klingeler, R. (2019). Magnetic properties of high-pressure optical floating-zone grown LaNiO₃ single crystals. Journal of Crystal Growth, 524, 125157.

• Zheng, H., Zhang, J., Wang, B., Phelan, D., Krogstad, M. J., Ren, Y., Phelan, W. A., Chmaissem, O., Poudel, B., Mitchell, J. F. (2019). High pO₂ Floating Zone Crystal Growth of the Perovskite Nickelate PrNiO₃. Crystals, 9(7), 324.

• Hergett, W., Neef, C., Wadepohl, H., Meyer, H.-P., Abdel-Hafiez, M. M., Ritter, C., Thauer, E., Klingeler, R. (2019). High-pressure optical floating-zone growth of Li₂FeSiO₄ single crystals. Journal of Crystal Growth, 515, 37-43.

• Puphal, P., Allenspach, S., Rüegg, C., Pomjakushina, E. (2019). Floating Zone Growth of Sr Substituted Han Purple: Ba_0.9Sr_0.1CuSi₂O₆. Crystals, 9(5), 273.

• Hergett, W., Jonak, M., Werner, J., Billert, F., Sauerland, S., Koo, C., Neef, C., Klingeler, R. (2019). Synthesis and magnetism of a Li₂FeSiO₄ single crystal. Journal of Magnetism and Magnetic Materials, 477, 1-3.

• Zhuang, L., Feng, H., Huang, S., Zhang, Z., Yong, W., Mao, R., Zhao, J. (2019). The luminescent properties comparison of RE₂O₃:Eu (RE = Lu, Y, Sc) with high and low Eu doping concentrations. Journal of Alloys and Compounds, 781 302-307.

• Puphal, P., Mielke, C., Kumar, N., Soh, Y., Shang, T., Medarde, M., White, J. S., Pomjakushina, E. (2019). Bulk single-crystal growth of the theoretically predicted magnetic Weyl semimetals RAlGe (R = Pr, Ce). Physical Review Materials, 3, 024204.

• Phelan, W. A., Zahn, J., Kennedy, Z., McQueen, T. M. (2019). Pushing boundaries: High pressure, supercritical optical floating zone materials discovery. Journal of Solid State Chemistry, 270, 705-709.

• Ryu, G., Guo, H., Zhao, L., Fernández‐Díaz, M. T., Drees, Y., Li, Z. W., Hu, Z., Komarek, A. C. (2018). Single Crystal Growth and Magnetic Properties of High Oxidation State Material Ba₂CoO₄. Physica Status Solidi RRL - Rapid Research Letters 13, 1800537.

• Wan, H., Wang, Y., Zhuang, L., Huang, S., Zhang, Z., Xu, Z., Mao, R., Feng, H., Zhao, J. (2018). Photoluminescence, scintillation properties and trap states of La2Si2O7Ce single crystal. Materials Research Express, 5, 8.

• Wang, B.-X., Rosenkranz, S., Rui, X., Zhang, J., Ye, F., Zheng, H., Klie, R. F., Mitchell, J. F., Phelan, D. (2018). Antiferromagnetic defect structure in LaNiO_3−δ single crystals. Physical Review Materials, 2, 064404.

• Zheng, H., Zhang, J., Stoumpos, C. C., Ren, Y., Chen, Y.-S., Dally, R., Wilson, S. D., Islam, Z., Mitchell, J. F. (2018). Controlled vapor crystal growth of Na₄Ir₃O₈: A three-dimensional quantum spin liquid candidate. Physical Review Materials, 2, 043403.

• Guo, H., Li, Z. W., Zhao, L., Hu, Z., Chang, C. F., Kuo, C.-Y., Schmidt, W., Piovano, A., Pi, T. W., Sobolev, O., Khomskii, D. I., Tjeng, L. H. & Komarek, A. C. (2018). Antiferromagnetic correlations in the metallic strongly correlated transition metal oxide LaNiO₃. Nature Communications, 9:43.

• Li, Z. W., Guo, H., Hu, Z., Chan, T. S., Nemkovski, K., & Komarek, A. C. (2017). Single-crystal growth and physical properties of 50% electron-doped rhodate Sr_1.5La_0.5RhO₄ Physical Review Materials, 1(4), 044005.

• Schreiber, N. J., Zhang, J., Zheng, H., Freeland, J. W., Chen, Y. S., Mitchell, J. F., & Phelan, D. (2017). Single crystal growth and structural evolution across the 1st order valence transition in (Pr_{1− y}Y_y)_{1− x}Ca_xCoO_3-δ. Journal of Solid State Chemistry, 254, 69-74.

• Zhang, J., Botana, A. S., Freeland, J. W., Phelan, D., Zheng, H., Pardo, V., ... & Mitchell, J. F. (2017). Large orbital polarization in a metallic square-planar nickelate. Nature Physics, 13, 864–869.

• Zhang, J., Zheng, H., Ren, Y., & Mitchell, J. F. (2017). High-Pressure Floating-Zone Growth of Perovskite Nickelate LaNiO₃ Single Crystals. Crystal Growth & Design, 17(5), 2730-2735.

• Neef, C., Wadepohl, H., Meyer, H. P., & Klingeler, R. (2017). High-pressure optical floating-zone growth of Li(Mn,Fe)PO₄ single crystals. Journal of Crystal Growth, 462, 50-59.

• Shen, Y., Li, Y. D., Wo, H., Li, Y., Shen, S., Pan, B., Wang Q., Walker H. C., Steffens P., Boehm M., Hao Y., Quintero-Castro D. L., Harriger L. W., Frontzek M. D., Hao L., Meng S., Zhang Q., Chen G., Zhao J. (2016). Evidence for a spinon Fermi surface in a triangular-lattice quantum-spin-liquid candidate. Nature, 540, 559–562.

• Zhang, J., Chen, Y. S., Phelan, D., Zheng, H., Norman, M. R., & Mitchell, J. F. (2016). Stacked charge stripes in quasi-2D trilayer nickelate La₄Ni₃O₈.PNAS, 113 (32) 8945-8950.

• Guo, H., Hu, Z., Pi, T. W., Tjeng, L. H., & Komarek, A. C. (2016). Single Crystal Growth of Pure Co3+ Oxidation State Material LaSrCoO₄. Crystals, 6(8), 98.

• Li, Z. W., Liu, C. F., Skoulatos, M., Tjeng, L. H., & Komarek, A. C. (2015). Floating zone growth of Ba-substituted ruthenate Sr_2−xBa_xRuO₄. Journal of Crystal Growth, 427, 94-98.

• Cao, H. B., Zhao, Z. Y., Lee, M., Choi, E. S., McGuire, M. A., Sales, B. C., Zhou, H. D., Yan,  J.-Q., and Mandrus, D. G. (2015). High pressure floating zone growth and structural properties of ferrimagnetic quantum paraelectric BaFe₁₂O₁₉. APL Materials, 3, 062512.

• Steil, D., Schmitt, O., Fetzer, R., Kubota, T., Naganuma, H., Oogane, M., Ando, Y., Rodan, S., Blum, C. , Balke, B., Wurmehl, S., Aeschlimann, M., and Cinchetti, M. (2015). Impact of local order and stoichiometry on the ultrafast magnetization dynamics of Heusler compounds. Journal of Physics D: Applied Physics, 48(16), 164016.

• Zhang, J., Zheng, H., Malliakas, C. D., Allred, J. M., Ren, Y., Li, Q. A., Han, T.-H. & Mitchell, J. F. (2014). Brownmillerite Ca₂Co₂O₅: Synthesis, Stability, and Re-entrant Single Crystal to Single Crystal Structural Transitions. Chemistry of Materials, 26(24), 7172-7182.

• Bauer, A., Regnat, A., Blum, C. G., Gottlieb-Schönmeyer, S., Pedersen, B., Meven, M., Wurmehl, S, Kuneš, J & Pfleiderer, C. (2014). Low-temperature properties of single-crystal CrB₂. Physical Review B, 90(6), 064414. (Also on archiv.org.)

• Omar, A., Blum, C. G., Löser, W., Büchner, B., & Wurmehl, S. (2014). Effect of annealing on spinodally decomposed Co₂CrAl grown via floating zone technique. Journal of Crystal Growth, 401, 617-621. (Also on arxiv.org.)

• Brasse, M., Chioncel, L., Kuneš, J., Bauer, A., Regnat, A., Blum, C. G. F., Wurmehl, S., Pfleiderer, C., Wilde, M. A. & Grundler, D. (2013). de Haas–van Alphen effect and Fermi surface properties of single-crystal CrB₂. Physical Review B, 88(15), 155138. (Also on arxiv.org.)

• Omar, A., Dimitrakopoulou, M., Blum, C. G. F., Wendrock, H., Rodan, S., Hampel, S., Löser, W., Büchner, B., & Wurmehl, S. (2013). Phase Dynamics and Growth of Co₂Cr_1–xFe_xAl Heusler Compounds: A Key to Understand Their Anomalous Physical Properties. Crystal Growth & Design, 13(9), 3925-3934.

• Blum, C. G., Ouardi, S., Fecher, G. H., Balke, B., Kozina, X., Stryganyuk, G., Ueda, S., Kobayashi, K., Felser, C., Wurmehl, S., & Büchner, B. (2011). Exploring the details of the martensite–austenite phase transition of the shape memory Heusler compound Mn₂NiGa by hard x-ray photoelectron spectroscopy, magnetic and transport measurements. Applied Physics Letters, 98(25), 252501.

• Wizent, N., Behr, G., Löser, W., Büchner, B., & Klingeler, R. (2011). Challenges in the crystal growth of Li₂CuO₂ and LiMnPO₄. Journal of Crystal Growth, 318(1), 995-999.

• Cao, C., Löser, W., Behr, G., Klingeler, R., Leps, N., Vinzelberg, H., & Büchner, B. (2011). Self-flux growth of large EuCu₂Si₂ single crystals. Journal of Crystal Growth, 318(1), 1043-1047.

• Behr, G., Löser, W., Wizent, N., Ribeiro, P., Apostu, M. O., & Souptel, D. (2010). Influence of heat distribution and zone shape in the floating zone growth of selected oxide compounds. Journal of materials science, 45(8), 2223-2227.

• Blum, C. G. F., Jenkins, C. A., Barth, J., Felser, C., Wurmehl, S., Friemel, G., Hess, C, Behr, G, Büchner, B, Reller, A, S. Riegg, S., Ebbinghaus, S. G., Ellis, T., Jacobs, P. J., Kohlhepp, J. T. & Swagten, H. J. M. (2009). Highly ordered, half-metallic Co₂FeSi single crystals. Applied Physics Letters, 95(16), 161903.

• Wizent, N., Behr, G., Lipps, F., Hellmann, I., Klingeler, R., Kataev, V., Löser, W., Sato, N. & Büchner, B. (2009). Single-crystal growth of LiMnPO₄ by the floating-zone method. Journal of Crystal Growth, 311(5), 1273-1277. (Also on uni-heidelberg.de.)

• Behr, G., Löser, W., Souptel, D., Fuchs, G., Mazilu, I., Cao, C., Köhler, A., Schultz, L. & Büchner, B. (2008). Crystal growth of rare earth-transition metal borocarbides and silicides. Journal of Crystal Growth, 310(7), 2268-2276.

• Phelan, W. A., Zahn, J., Kennedy, Z., McQueen, T. M. (2019). Pushing boundaries: High pressure, supercritical optical floating zone materials discovery. Journal of Solid State Chemistry, 270, 705-709.

• Wizent, N., Behr, G., Löser, W., Büchner, B., & Klingeler, R. (2011). Challenges in the crystal growth of Li₂CuO₂ and LiMnPO₄. Journal of Crystal Growth, 318(1), 995-999.

• Behr, G., Löser, W., Wizent, N., Ribeiro, P., Apostu, M. O., & Souptel, D. (2010). Influence of heat distribution and zone shape in the floating zone growth of selected oxide compounds. Journal of materials science, 45(8), 2223-2227.

• Behr, G., Löser, W., Souptel, D., Fuchs, G., Mazilu, I., Cao, C., Köhler, A., Schultz, L. & Büchner, B. (2008). Crystal growth of rare earth-transition metal borocarbides and silicides. Journal of Crystal Growth, 310(7), 2268-2276.

• Souptel, D., Löser, W., & Behr, G. (2007). Vertical optical floating zone furnace: principles of irradiation profile formation. Journal of Crystal Growth, 300(2), 538-550. (Also on caltech.edu.)

• Palme, M., Riehemann, S., Horst, A., Souptel, D., Behr, G. (2004). Optical simulation of a radiation heating / Optische Simulation einer Strahlungsheizung. Fraunhofer IOF Annual Report 2004, 70-71.

Fig: First HKZ generation, working facility of MaTecK GmbH, Location ScIDre GmbH Dresden