Project Details
Projekt
SPP 1239: Modification of Microstructure and Shape of Solid Materials by External Magnetic Fields
Subject Area
Materials Science and Engineering
Mathematics
Physics
Mathematics
Physics
Term
from 2006 to 2013
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 18470518
Currently applied adaptive materials like piezoceramics or magnetostrictive materials can change their shape by applying an external electric or magnetic field and reach relative length changes of 0.1 to 0.2 per cent. Especially piezoceramic functional materials had been a key requirement for several innovations. Applications range from the scanning tunnelling microscope to novel injection valves.
Another class of adaptive materials are the shape memory alloys, which can exhibit a reversible shape change due to temperature variation. The origin of this effect is the phase transformation between the high temperature "austenite" phase and the low temperature "martensite" phase. In single crystals of special magnetic shape memory materials in 1996 a further, fundamentally new actuation mechanism had been discovered in the martensite phase. It was observed, that already comparably low magnetic fields (< 1 Tesla) can be sufficient to move twin boundaries contained in the material. Since the twin boundaries are separating areas of different crystallographic orientations, their displacement leads to a reorientation of the crystal. This allows controlling the microstructure and shape of the sample by applying magnetic fields. The observed change in length of up to 10 per cent is, compared to magnetostrictive or piezoceramic materials, by more than two orders of magnitude higher. Due to the unique combination of very large strain, high energy density and relatively high actuation frequencies magnetic shape memory alloys thus allow novel applications, which are not possible with conventional adaptive materials.
Within the area A of the Priority Programme, the fundamentals of this material class are examined. Models are developed which describe the coupling of microstructure and magnetism from the atomistic dimensions to the device scale. Additionally, novel magnetic shape memory alloys are prepared and examined which promise better properties compared to today's materials.
Within area B, new and efficient preparation routes for bulk materials are developed. These materials are integrated into novel actuator and damping systems. An additional focus is on the characterisation of these materials with high lateral and temporal resolution.
Area C develops thin films with appropriate microstructure and texture. It is the aim to use the high miniaturisation potential of the magnetic shape memory effect and to develop novel micro actuator and sensor systems.
Another class of adaptive materials are the shape memory alloys, which can exhibit a reversible shape change due to temperature variation. The origin of this effect is the phase transformation between the high temperature "austenite" phase and the low temperature "martensite" phase. In single crystals of special magnetic shape memory materials in 1996 a further, fundamentally new actuation mechanism had been discovered in the martensite phase. It was observed, that already comparably low magnetic fields (< 1 Tesla) can be sufficient to move twin boundaries contained in the material. Since the twin boundaries are separating areas of different crystallographic orientations, their displacement leads to a reorientation of the crystal. This allows controlling the microstructure and shape of the sample by applying magnetic fields. The observed change in length of up to 10 per cent is, compared to magnetostrictive or piezoceramic materials, by more than two orders of magnitude higher. Due to the unique combination of very large strain, high energy density and relatively high actuation frequencies magnetic shape memory alloys thus allow novel applications, which are not possible with conventional adaptive materials.
Within the area A of the Priority Programme, the fundamentals of this material class are examined. Models are developed which describe the coupling of microstructure and magnetism from the atomistic dimensions to the device scale. Additionally, novel magnetic shape memory alloys are prepared and examined which promise better properties compared to today's materials.
Within area B, new and efficient preparation routes for bulk materials are developed. These materials are integrated into novel actuator and damping systems. An additional focus is on the characterisation of these materials with high lateral and temporal resolution.
Area C develops thin films with appropriate microstructure and texture. It is the aim to use the high miniaturisation potential of the magnetic shape memory effect and to develop novel micro actuator and sensor systems.
DFG Programme
Priority Programmes
Projects
- Ab initio investigation of temperature dependent effects in magnetic shape memory Heusler alloys (Applicant Hickel, Tilmann )
- Basic research of the influence of real structure on magnetic field induced strain (MFIS) in NiMnGa alloys - Magnetic field induced strain (MFIS) in textured polycrystalline ferromagnetic martensitic NiMnGa alloys (Applicants Böhm, Andrea ; Roth, Stefan )
- Basic research of the influence of real structure on the magnetic field induced strain in NiMnGa alloys - Structure and properties of twin boundaries in NiMnGa alloys (Applicant Skrotzki, Werner )
- Characterization of the micro- and nanostructure of magnetic shape memory materials by Transmission Electron Microscopy (TEM). (Applicant Kienle, Lorenz )
- Coordination of the SPP 1239 (Applicant Fähler, Sebastian )
- Development of MSMA-Driven Actuators based on Standardization of Single Crystal Growth, Treatment and Quality Assessment (Applicant Raatz, Annika )
- Domain structures and dynamics in Ferromagnetic shape memory materials: Theory and Experiment - Continuum models of magnetic shape memory materials: mathematics (Applicants Müller, Stefan ; Otto, Felix )
- Domain structures and dynamics in Ferromagnetic shape memory materials: Theory and Experiment - Continuum models of magnetic shape memory materials: modelling (Applicant Rößler, Ulrich K. )
- Domain structures and dynamics in Ferromagnetic shape memory materials: Theory and Experiment - Dynamic metallographic and magneto-optical polarization microscopy of MSMA systems (Applicant McCord, Jeffrey )
- Exploitation and Transfer of Results of the SPP 1239 (Applicant Quandt, Eckhard )
- Fe-Pd-X Thin Film-Polymer Composites for Sensor Applications - Development of new miniaturized sensors using composites of ferromagnetic shape memory thin films and polymers (Applicant Quandt, Eckhard )
- Fe-Pd-X Thin Film-Polymer Composites for Sensor Applications - Extrinsic properties of epitaxial Fe-Pd MSM films (Applicant Fähler, Sebastian )
- Fe-Pd-X Thin Film-Polymer Composites for Sensor Applications - First-principles evaluation of magneto-crystalline anisotropy and related intrinsic properties of Fe-Pd-X: optimization of alloy composition (Applicant Richter, Manuel )
- Integrated Microactuator Systems Emphasizing Ni-Mn-Ga Films with a Tailored Microstructure INTACT - Design and System Integration of Microactuators with Discrete and Thin-Film MSM Elements (Applicant Gatzen, Hans-Heinrich )
- Integrated Microactuator Systems Emphasizing Ni-Mn-Ga Films with a Tailored Microstructure - INTACT - Micromachining and Integration of Ni-Mn-ga Film Actuators for Microsystems Applications (Applicant Kohl, Manfred )
- Magnetic, magnetoelastic and dynamical properties of martensitic Heusler alloys (Applicant Acet, Mehmet )
- Magnetic, magnetoelastic and dynamical properties of martensitic Heusler alloys - Ab initio and semi-empiric simulations of structural changes of magnetic shape memory systems by external magnetic fields (Applicant Entel, Peter )
- Magnetic, magnetoelastic and dynamical properties of matensitic Heusler alloys (Applicant Neuhaus, Jürgen )
- Magnetic shape-memory alloys as active materials for vibration damping (Applicant Janocha, Hartmut )
- Mathematical Modeling and Simulation of Microstructured Magnetic-Shape-Memory Devices (Applicant Conti, Sergio )
- Microactuator Systems Based on Epitaxial Ni-Mn-Ga Films with Magnetic Shape Memory Effect (EPITACT) (Applicants Fähler, Sebastian ; Kohl, Manfred )
- Microstructure of epitaxial films of the magnetic shape memory material Ni2MnGa (Applicant Jakob, Gerhard )
- PAk 1: Fe-Pd-X Thin Film-Polymer Composites for Sensor Applications - Combinatorial Development of New Ferromagnetic Shape Memory Thin Films with Improved Intrinsic Properties (Applicant Ludwig, Alfred )
- PAK 5: "Integrated Microactuator Systems Emphasizing Ni-Mn-Ga Films with a Tailored Microstructure" INTACT - Mechanical, magnetic and morphological properties of vapor desposited magnetic shape memory alloy thin films (Applicant Mayr, Stefan )
- Paket 1 "Fe-Pd-X Thin Film-Polymer Composites for Sensor Applications" - Ab initio evaluation of phase stability, magnetism and twon boundary mobility in ternary Fe-based shape memory materials (Applicant Gruner, Markus )
- Phase-field modelling of magnetically induced microstructure evolution in martensitic polycrystals (Applicant Nestler, Britta )
- Polymer bonded textured composites with single crystalline NiMn-based MSM particles for magnetic-field controlled dampers and actuators (Applicant Gutfleisch, Oliver )
Spokesperson
Privatdozent Dr. Sebastian Fähler
