Since 2000, I have been leading a project group at the EAH that focuses on the development of functional ceramic materials. In addition to the full-time project staff, there are frequent opportunities for dedicated students to contribute as student assistants.
- Performance Enhancement of Ca₃Co₄O₉-Based Transverse Multilayer Thermoelectric Generators for Low-Power Applications
A. Ibrahim, A. Bochmann, R. Löhnert, B. Mieller, L. Wilde, B. Capraro, M. Stelter, J. Töpfer, J. Am. Ceram. Soc. 109 (2026) e70656. https://doi.org/10.1111/jace.70656 - Phase Formation During Sintering of Hexagonal W-Type Sr Ferrite in Reduced Oxygen Partial Pressure
T. Schulz, G. Obara, A. Chetouani, J.M. Le Breton, J. Töpfer
, *Ceramics International* 52 (2026) 28891–38899
https://doi.org/10.1016/j.ceramint.2026.06.343 - Thermodynamics of the W-type ferrite solid-solution system SrCoxFe18-xO27
S. Nakai, T. Waki, Y. Tabata, H. Ohta, M. Kato, C. Teichmann, J. Töpfer, H. Nakamura,
Journal of the Ceramic Society of Japan 134 [8] 543–554 2026
https://doi.org/10.2109/jcersj2.26038
- Fe–Si–Cr Alloy–Ni–Cu–Zn Ferrite Composite Multilayer Inductors: Fabrication, Co-firing, and Magnetic Performance
H.I. Hsiang, Y.C. Hsu, W.H. Lee, C. Priese, J. Töpfer
J. Electron. Mater. (2025).
https://doi.org/10.1007/s11664-025-11856-0 - Magnetic Texturing of Self-Biasing Hexagonal Ferrite Tapes for Integration in LTCC Microwave Modules
M. Heidenreich, D. Schabbel, B. Capraro, J. Töpfer
Ceramics International 51 (2025) 23578–23585.
https://doi.org/10.1016/j.ceramint.2025.03.045 - Boosting the thermoelectric performance of Ca₃Co₄O₉ ceramics through optimized precursor powder particle size
A. Ibrahim, J. Töpfer
J. Mater. Res. 40 (2025) 1773–1785.
https://doi.org/10.1557/s43578-025-01610-x - Effects of Reducing Agents and Pre-sintering Annealing on Phase Changes during the Sintering of W-type Ferrites
G. Obara, T. Takahashi, T. Honda, T. Schulz, J. Töpfer
IEEJ Transactions on Fundamentals and Materials, 145 (2025) 211–216.
https://doi.org/10.1541/ieejfms.145.211
Lead-free KNNLT piezoceramic multilayer actuators with Ni electrodes cofired under low oxygen partial pressure
W.M. Alkanj, A. Kynast, M. Töpfer, F. Schubert, J. Töpfer
Open Ceramics 17 (2024) 100508
https://doi.org/10.1016/j.oceram.2023.100508Hexagonal ferrites for self-biasing circulators integrated in LTCC microwave modules
M. Heidenreich, J. Schur, J. Müller, W. Gitzel, A.F. Jacob, J. Töpfer
Mat. Res. Bull. 178 (2024) 112878
https://doi.org/10.1016/j.materresbull.2024.112878Assessment of artificial anisotropic materials for transverse thermoelectric generators
R. Löhnert, A. Bochmann, A. Ibrahim, J. Töpfer
Phys. Status Solidi A (2024) 2400321
https://doi.org/10.1002/pssa.202400321Ontology-based data acquisition, refinement, and utilization in the development of a multilayer ferrite inductor
B. Mieller, S. Ben Hassine, J. Töpfer, C. Priese, A. Bochmann, B. Capraro, S. Stark, U. Partsch, C. Fresemann
Adv. Eng. Mater. (2024) 2401042
https://doi.org/10.1002/adem.202401042
- Thermoanalytic Characterization of Binder Burnout and Sintering of Lead-Free Piezoelectric KNNLT Multilayer Laminates with Ni Electrodes
M. W. Alkanj, A. Kynast, M. Töpfer, F. Schubert, J. Töpfer
J. Therm. Anal. Calor. (2023)
https://doi.org/10.1007/s10973-022-11844-0 - NiMn₂O₄ revisited: Temperature-dependent cation distribution from in situ neutron diffraction and thermopower studies
J. Dinger, T. Friedrich, T. Reimann, J. Töpfer
J. Am. Ceram. Soc. 106 (2023) 1834–1847.
https://doi.org/10.1111/jace.18865 - Fabrication of self-biased circulators with integrated hexagonal microwave ferrites using LTCC technology
M. Heidenreich, J. Schur, J. Müller, B. Capraro, W. Gitzel, A.F. Jacob, J. Töpfer, Jörg
Ceramic Forum International cfi/Ber. DKG 100 [2] (2023) E38–E46.
- Synthesis and Properties of Lead-Free BNT-BT-xCZ Ceramics as High-Temperature Dielectrics
T. Schulz, V. Veerapandiyan, M. Deluca, J. Töpfer
Mat. Res. Bull. 145 (2022) 111560.
https://doi.org/10.1016/j.materresbull.2021.111560 - Large Thermal Expansion LTCC System for Cofiring with Integrated Functional Ceramic Layers
B. Capraro, M. Heidenreich, J. Töpfer
Materials 15 (2022) 564.
https://doi.org/10.3390/ma15020564 - Sintering and Electrical Properties of Cu-Substituted Zn-Co-Ni-Mn Spinel Ceramics for NTC Thermistor Thick Films
C. Teichmann, J. Töpfer
J. Europ. Ceram. Soc. 42 (2022) 2261–2267.
https://doi.org/10.1016/j.jeurceramsoc.2021.12.078 - Tuning of high-temperature dielectric properties in the (Bi₀.₅Na₀.₅)TiO₃–BaTiO₃–CaZrO₃
system T. Schulz, A. Knauer, P. Schaaf, J. Töpfer
Ceram. Intl. 48 (2022) 22187–22195
https://doi.org/10.1016/j.ceramint.2022.04.220 - The effect of microstructure on the initial permeability of Ni-Zn ferrite
C. Priese, J. Töpfer
J. Magn. Magn. Mater. 560 (2022) 169581.
https://doi.org/10.1016/j.jmmm.2022.169581 - Enhancing the thermoelectric properties of CaMnO₃-d via optimal substituent selection
R. Löhnert, J. Töpfer
J. Solid State Chem. 315 (2022) 123437
https://doi.org/10.1016/j.jssc.2022.123437 - Oxidation Behavior, Insulation Resistance, and Permeability of FeSiCr Alloys for Multilayer Inductors
C. Priese, J. Töpfer,
Alloys 1 (2022) 288–297.
https://doi.org/10.3390/alloys1030019
- Low pO2 sintering and reoxidation of lead-free KNNLT piezoceramic laminates
T. Reimann, S. Fröhlich, A. Bochmann, A. Kynast, M. Töpfer, E. Hennig, J. Töpfer
J. Europ. Ceramic Soc. 41 (2021) 344–351. - Phase Formation, Microstructure, and Permeability of Fe-Deficient Ni–Cu–Zn Ferrites, (I): Effect of Sintering Temperature.
C. Priese, J. Töpfer
*Magnetochemistry* 7 (2021) 118. https://doi.org/10.3390/magnetochemistry7080118 - Ni‐Cu‐Zn ferrites with high Curie temperature for multilayer inductors with increased operating temperatures
T. Reimann, B. Capraro, H. Bartsch, J. Töpfer
Intl. J. Appl. Ceram. Techn. 18 (2021) 129–137. - Low-temperature sintered Ni–Zn–Co–Mn–O spinel oxide ceramics for multilayer NTC thermistors
T. Reimann, J. Töpfer
J. Mater. Science: Mat. Electr. 32(8) (2021) 10761–10768.
DOI 10.1007/s10854-021-05733-9 - Cofiring of LTCC multilayer assemblies with integrated NTC thermistor temperature sensor layers
T. Reimann, S. Barth, B. Capraro, H. Bartsch, J. Töpfer
Ceram. Inter. 47 (2021) 27849–27853.
https://doi.org/10.1016/j.ceramint.2021.06.213
- Multilayer ferrite inductors for use at higher temperatures
H. Bartsch, S. Thiele, J. Müller, D. Schabbel, B. Capraro, S. Grund, J. Töpfer
Microelectronics Inter. 37 (2020) 73–78. - Phase stability and magnetic properties of SrFe18O27 W-type hexagonal ferrite
T. Reimann, T. Schmidt, J. Töpfer
J. Am. Ceram. Soc. 103 (2020) 324–334. - Ga-, Y-, and Sc-substituted M-type ferrites for self-biasing circulators in LTCC microwave modules
M. Heidenreich, X. Ma, W. Gitzel, A. Jacob, B. Capraro, J. Töpfer
AIP Advances 10 (2020) 025315. - Circuit-Board-Integrated Transformers: Design and Manufacture
R. Matz, T. Rabe, J. Töpfer, S. Ziesche
J. Ceram. Sci. Technol., 11 (2020) 44–61. - Phase Formation and Saturation Magnetization of La-Zn-Substituted M-Type Strontium Ferrites
T. Schmidt, D. Seifert, J. Töpfer
J. Magn. Magn. Mater. 508 (2020) 166887 - Hexavalent (Me‐W/Mo)‐modified (Ba,Ca)TiO₃‐Bi(Mg,Me)O₃ perovskites for high‐temperature dielectrics
T. Schulz, V.K. Veerapandiyan, T. Gindel, M. Deluca, J. Töpfer
J. Am. Ceram. Soc. 103 (2020) 6881–6892.
- Sintering, Microwave Properties, and Circulator Applications of Textured Sc-Substituted M-Type Ferrite Thick Films
S. Bierlich, T. Reimann, F. Gellersen, A. Jacob, J. Töpfer
J. Europ. Ceram. Soc. 39 (2019) 3077–3081 - Transverse thermoelectric multilayer generator with bismuth-substituted calcium cobaltite: Design optimization through variation of tilt angle
A. Bochmann, T. Reimann, T. Schulz, S. Teichert, J. Töpfer
J. Europ. Ceram. Soc. 39 (2019) 2923–2929 - Synthesis and magnetic properties of hard/soft SrAl₂Fe₁₀O₁₉/Fe(FeCo₂) nanocomposites
M. Kahnes, J. Töpfer
J. Magn. Magn. Mater. 480 (2019) 40–46 - Phase formation and magnetic properties of CoFe₂O₄/CoFe₂ nanocomposites
M. Kahnes, R. Müller, J. Töpfer
Mater. Chem. Phys. 227 (2019) 83–89 - Phase formation, magnetic properties, and phase stability in a reducing atmosphere of M-type strontium hexaferrite nanoparticles synthesized via a modified citrate process
C. Bohlender, M. Kahnes, R. Müller, J. Töpfer
J. Mater. Sci. 54 (2019) 1136–1146
- Low-Temperature Sintering of BaTiO₃ Positive Temperature Coefficient of Resistivity (PTCR) Ceramics
C. Teichmann, J. Töpfer
J. Mater. Sci.: Mater. Electr. 29 (2018) 17881–17886 - Synthesis, doping, and electrical bulk response of (Bi₁/₂Na₁/₂)_xBa₁₋_xTiO₃ + CaO-based ceramics with a positive temperature coefficient of resistivity (PTCR)
D. Mächler, R. Schmidt, J. Töpfer
J. Alloys Comp. 762 (2018) 209–215 - Sintering behavior, microstructure, and thermoelectric properties of calcium cobaltite thick films for transverse thermoelectric multilayer generators
T. Schulz, T. Reimann, A. Bochmann, A. Vogel, B. Capraro, B. Mieller, S. Teichert, J. Töpfer
J. Europ. Ceram. Soc. 38 (2018) 1600–1607 - Oxide multilayer thermoelectric generators
J. Töpfer, T. Reimann, T. Schulz, A. Bochmann, B. Capraro, S. Barth, A. Vogel, S. Teichert
Intl. J. Appl. Ceram. Techn. DOI: 10.1111/ijac.12822
- Fabrication of a Transverse Multilayer Thermoelectric Generator with Substituted Calcium Manganite
T. Reimann, A. Bochmann, A. Vogel, B. Capraro, S. Teichert, J. Töpfer
J. Am. Ceram. Soc. 100 (2017) 5700–5708 - Fabrication of a Transverse Multilayer Thermoelectric Generator with Substituted Calcium Manganite
T. Reimann, A. Bochmann, A. Vogel, B. Capraro, S. Teichert, J. Töpfer
J. Am. Ceram. Soc. 100 (2017) 5700–5708 - Evaluation of soft chemistry methods to synthesize Gd-doped CaMnO₃-sigma with improved thermoelectric properties
R. Löhnert, M. Stelter, J. Töpfer
Mater. Sci. Eng. B223 (2017) 185–193 - Effect of SiO₂ sintering additive on the positive temperature coefficient of resistivity (PTCR) behavior of (Bi₁/₂Na₁/₂)₀.₁Ba₀.₉TiO₃ + CaO ceramics
D. Mächler, J. Töpfer
Mater. Res. Bull. 89 (2017) 217–223 - Thermoelectric properties of Gd/W double-substituted calcium manganite
T. Reimann, J. Töpfer
J. Alloys Comp. 699 (2017) 788–795 - Low-temperature sintering and magnetic properties of Sc- and In-substituted M-type hexagonal barium ferrites for microwave applications
S. Bierlich, F. Gellersen, A. Jacob, J. Töpfer
Mater. Res. Bull. 86 (2017) 19–23
Members of the working group
Chemistry laboratory, materials diagnostics laboratory (thermal analysis, X-ray diffractometry), glass/ceramics laboratory
Consultation hours: Online (by prior arrangement by e-mail)
Highlights
Cover page of the *International Journal of Applied Ceramic Technology*
98th DKG Annual Meeting
Ernst Abbe University of Applied Sciences Jena / Hermsdorf (March 27–30, 2023)
Areas of Expertise
Functional Ceramic Materials / functional ceramics
Soft ferrites - Mn-Zn ferrites for power transmission / Mn-Zn power ferrites | Hard ferrites - Sr ferrites as permanent magnets / Sr ferrite permanent magnets |
Piezoelectric, ferromagnetic, and dielectric materials / piezo-, ferro-, and dielectric materials - piezoceramic materials (PZT, lead-free materials) - | Semiconducting ceramics - Thermoelectric oxides / synthesis and characterization of thermoelectric oxides |
Materials Chemistry
Solid-State Chemistry of Oxides - Conductivity and magnetic properties of oxides / charge transport and magnetic properties of oxides | Nonstoichiometry and defect chemistry of functional oxides - Thermoanalytic characterization of nonstoichiometry in oxides / thermoanalytic characterization of nonstoichiometry of oxides |
Functional Ceramic Coatings / Functional Ceramic Thick-Film Systems
LTCC Technology / Low-Temperature Ceramic Cofiring - Materials for multilayer systems / materials for multilayer components |