The premartensite phase of shape memory and magnetic shape memory alloys is believed to be a precursor state of the martensite phase with preserved austenite phase symmetry. The thermodynamic stability of the premartensite phase and its relation to the martensitic phase is still an unresolved issue, even though it is critical to the understanding of the functional properties of magnetic shape memory alloys.
In a recent study, scientists from the Max Planck Institute for Chemical Physics of Solids in Dresden demonstrated unambiguous evidence for macroscopic symmetry breaking leading to robust Bain distortion in the premartensite phase of 10% Pt-substituted Ni2MnGa using high resolution synchrotron x-ray diffraction study.
They show that the robust Bain-distorted premartensite phase results from another premartensite phase with preserved cubic-like symmetry through an isostructural phase transition. The Bain-distorted premartensite phase finally transforms to the martensite phase with additional Bain distortion on further cooling.
These results demonstrate that the premartensite phase should not be considered as a precursor state with the preserved symmetry of the cubic austenite phase. The gradual evolution of the Bain distortion can facilitate the emergence of an invariant habit plane. Therefore, such alloys may exhibit better reversibility due to lower hysteresis, which will enhance their applicability as magnetic actuators and in refrigeration technology.
The research at the Max Planck Institute for Chemical Physics of Solids (MPI CPfS) in Dresden aims to discover and understand new materials with unusual properties.
In close cooperation, chemists and physicists (including chemists working on synthesis, experimentalists and theoreticians) use the most modern tools and methods to examine how the chemical composition and arrangement of atoms, as well as external forces, affect the magnetic, electronic and chemical properties of the compounds.
New quantum materials, physical phenomena and materials for energy conversion are the result of this interdisciplinary collaboration.
The MPI CPfS ( www.cpfs.mpg.de ) is part of the Max Planck Society and was founded in 1995 in Dresden. It consists of around 280 employees, of which about 180 are scientists, including 70 doctoral students.
Dipl.-Übers. Ingrid Rothe | Max-Planck-Institut für Chemische Physik fester Stoffe
Understanding signaling pathways, fighting the spread of cancer
30.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
Immunobiology: Computer analysis fills gaps in antibody blueprint
30.11.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications."
Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the...
In a recent study, published in Nature, ICFO researchers Nicolas Maring, Pau Farrera, Dr. Kutlu Kutluer, Dr. Margherita Mazzera, and Dr. Georg Heinze led by ICREA Prof. Hugues de Riedmatten, have achieved an elementary "hybrid" quantum network link and demonstrated for the first time photonic quantum communication between two very distinct quantum nodes placed in different laboratories, using a single photon as information carrier.
Today, quantum information networks are ramping up to become a disruptive technology that will provide radically new capabilities for information processing...
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
30.11.2017 | Physics and Astronomy
30.11.2017 | Life Sciences
30.11.2017 | Materials Sciences