65 citations · 280 across the 8 of their papers we have counts for
8 papers
Building hierarchical martensite
Stefan Schwabe, Robert Niemann, Anja Backen +7
Martensitic materials show a complex, hierarchical microstructure containing structural domains separated by various types of twin boundaries. Several concepts exist to describe th…
Reversible tuning of magnetocaloric Ni-Mn-Ga-Co films on ferroelectric PMN-PT substrates
Benjamin Schleicher, Robert Niemann, Stefan Schwabe +4
Tuning functional properties of thin caloric films by mechanical stress is currently of high interest. In particular, a controllable magnetisation or transition temperature is desi…
Modulations in martensitic Heusler alloys originate from nanotwin ordering
Markus E. Gruner, Robert Niemann, Peter Entel +4
Heusler alloys exhibiting magnetic and martensitic transitions enable applications like magnetocaloric refrigeration and actuation based on the magnetic shape memory effect. Their…
Nucleation and growth of hierarchical martensite in epitaxial shape memory films
Robert Niemann, Anja Backen, Sandra Kauffmann-Weiss +7
Shape memory alloys often show a complex hierarchical morphology in the martensitic state. To understand the formation of this twin-within-twins microstructure, we examine epitaxia…
Geometry of Adaptive Martensite in Ni-Mn-based Heusler alloys
Robert Niemann, Sebastian Fähler
Modulated martensites play an important role in magnetic shape memory alloys, because all functional properties are closely connected to the twin microstructure and the phase bound…
Mesoscopic twin boundaries in epitaxial Ni-Mn-Ga films
Anja Backen, Sandra Kauffmann-Weiss, Christian Behler +6
Twin boundaries play an essential role in the use of magnetic shape memory alloy Ni-Mn-Ga as active material. Only if twin boundaries can be moved by an external magnetic field, hi…
Failure of the Maxwell relation for the quantification of caloric effects in ferroic materials
Robert Niemann, Oleg Heczko, Ludwig Schultz +1
Giant caloric effects were reported in elasto-, electro- and magnetocaloric materials near phase transformations. Commonly, their entropy change is indirectly evaluated by a Maxwel…
Modulated Martensite: Why it forms and why it deforms easily
Stefan Kaufmann, Robert Niemann, Thomas Thersleff +6
Diffusionless phase transitions are at the core of the multifunctionality of (magnetic) shape memory alloys, ferroelectrics and multiferroics. Giant strain effects under external f…