Thin films of the Ni-Mn-Ga ferromagnetic martensites due to a strong coupling of the structural and magnetic degrees of freedom are promising materials to be incorporated in novel sensors, actuators and magnetic MEMS.
In general, because the properties of polycrystalline thin films depend strongly on their microstructure, an important research area is concerned with the control of this microstructure, in particular the texture and internal stresses which develop during deposition and post-deposition annealing processes.
In this work, we the X-ray diffraction facility ANKA-Diff at the ANKA synchrotron source in Karlsruhe to study texture and internal stresses in Ni-Mn-Ga thin films sputter deposited on alumina ceramic. Two series of films of two different compositions consisting of 6 specimens each were fabricated by the magnetron deposition at ambient temperature. Each series of films was designed as the single layers of 0.1; 0.2; 0.4; 0.6; 1.0 and 5.0 micron thickness attached to alumina. Films on substrates were vacuum annealed at 1073 K for 36ks. Diffraction measurements were made at 423K. An in-house made temperature controlled heating unit was designed for this purpose. The selected value of temperature ensured that the films were in the austenitic cubic state. The texture measurements were performed using 2Theta scans at fixed Phi and Chi angles which were varied by the 10 deg. step in a range of 0 to 90 deg.
A drastic change of mutual intensities of 220 and 400 peaks as a function of Chi was found while Phi dependence was much less pronounced. An analysis of the results leads to the conclusion about different degree of {110}-type in-plane texture for the films of different thickness. The thickness dependence of the lattice parameter evidences a different degree of internal elastic stresses developed by the films during cooling after annealing.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/3868 must be provided.

1. Nanofabrication - direct write and replication patterning technologies in EUMINAfab
2. Nanofabrication - direct write and replication patterning technologies in EUMINAfab
3. Localization of rare-earth dopants in the lattice of nanocrystalline ZrO₂ - EXAFS study
4. Reversible and irreversible martensitic transformations in Fe-Pd and Fe-Pd-Co alloys
5. Transfer Bonding Technologies for Batch Fabrication of SMA Microactuators
6. Integration Technologies for Single-Crystalline NiMnGa Films
7. A Magnetization- and Strain-Dependent Free Energy Model for FEM Simulation of Magnetic Shape Memory Alloys
8. Training, constraints, and high-cycle magneto-mechanical properties of Ni-Mn-Ga magnetic shape-memory alloys
9. NiMnGa nanostructures produced by electron beam lithography and argon ion etching
10. Residual stress in Ni-Mn-Ga thin films deposited on different substrates
11. A Free Energy model for Magneto-Mechanically Coupled NiMnGa Single Crystals
12. Effects of Fe and Co addition on the magnetoresistance in Ni-Mn-Ga Films
13. Transformation behavior of Ni-Mn-Ga/Si(100) thin film composites with different film thicknesses
14. Effect of magnetic field on the TA₂ phonon branch softening in Ni₂MnGa
15. Localization of rare-earth dopants in the lattice of nanocrystalline ZrO₂ - EXAFS study
16. Properties of martensitic Ni-Mn-Ga thin films deposited on Mo foils
17. Pre-martensitic phenomena in a near stoichiometric Ni2MnGa polycrystalline alloy
18. MAGNETORESISTANCE OF Ni-Mn-Ga THIN FILMS IN THE VICINITY OF MAGNETOSTRUCTURAL TRANSFORMATION
19. Magnetomechanical Properties of Polycrystalline Ni-Mn-Ga Thin Film Actuators
20. The broadband magneto-electric energy conversion by the NiMnGa single crystal/piezoceramic system
21. Neutron study of the martensitic transformation in Ni-Fe-Ga alloys
22. Stress-temperature relationship in a Ni-Mn-Ga single crystal
23. Ferromagnetic Shape Memory Microscanner with Large Deflection Angles
24. PROPERTIES OF SPUTTER-DEPOSITED Ni-Mn-Ga THIN FILMS
25. DEPENDENCE OF THE MAGNETIC ANISOTROPY ON THE THICKNESS AND ANNEALING OF SPUTTER-DEPOSITED Ni-Mn-Ga THIN FILMS
26. Coupled simulation of the thermo-magneto-mechanical properties of a Ni-Mn-Ga actuator
27. Ferromagnetic Shape Memory Microscanner System for Automotive Applications