by H Rumpf, J Feydt, Daniel Lewandowski, B Ludwig, B Winzek, E Quandt, P Zhao, M Wuttig
Abstract:
NiMnGa thin films have been deposited by magnetron sputtering on Mo substrates using a Ni50Mn30Ga20 powder metallurgical target. Independent from variation of substrate temperature during the sputtering process the deposited films are found to be polycrystalline. X-ray diffraction patterns show a decreasing peak width and a shift to slightly higher Bragg angles with increasing substrate temperature during sputtering, which is even amplified when subsequent rapid thermal annealing is applied. Annealing temperatures above 500°C lead to a remarkable enhancement of the shape memory effect as well as of the magnetostriction. Temperature induced martensitic transformations have been measured by a cantilever deflection technique and a cantilever resonance method. Martensitic start temperatures (MS) range between 50 and 90°C depending on composition and annealing temperature. Stress relief upon the martensitic transformation ranges between 200 and 300 MPa whereas the magnetostrictive coupling constant b is about 2 MPa. Magnetization measurements and Curie temperature determination reveal ferromagnetic behavior within the temperature range of the martensitic transformation.
Reference:
Shape memory effect and magnetostriction of sputtered NiMnGa thin films (H Rumpf, J Feydt, Daniel Lewandowski, B Ludwig, B Winzek, E Quandt, P Zhao, M Wuttig), In Smart Structures and Materials 2003: active materials: behavior and mechanics (Dimitris C. Lagoudas (ed), ed.), SPIE — The International Society for Optical Engineering, 2003.
Bibtex Entry:
@InProceedings{ Rumpf2003,
author = {Rumpf, H and Feydt, J and Lewandowski, Daniel and Ludwig, B and Winzek, B and Quandt, E and Zhao, P and Wuttig, M},
title = {Shape memory effect and magnetostriction of sputtered NiMnGa thin films},
booktitle = {Smart Structures and Materials 2003: active materials: behavior and mechanics},
year = {2003},
editor = {Dimitris C. Lagoudas (ed)},
pages = {191-199},
address = {San Diego},
publisher = {SPIE -- The International Society for Optical Engineering},
abstract = {NiMnGa thin films have been deposited by magnetron sputtering on Mo substrates using a Ni50Mn30Ga20 powder metallurgical target. Independent from variation of
substrate temperature during the sputtering process the deposited films are found to be polycrystalline. X-ray diffraction patterns show a decreasing peak width
and a shift to slightly higher Bragg angles with increasing substrate temperature during sputtering, which is even amplified when subsequent rapid thermal
annealing is applied. Annealing temperatures above 500°C lead to a remarkable enhancement of the shape memory effect as well as of the magnetostriction.
Temperature induced martensitic transformations have been measured by a cantilever deflection technique and a cantilever resonance method. Martensitic start
temperatures (MS) range between 50 and 90°C depending on composition and annealing temperature. Stress relief upon the martensitic transformation ranges between
200 and 300 MPa whereas the magnetostrictive coupling constant b is about 2 MPa. Magnetization measurements and Curie temperature determination reveal
ferromagnetic behavior within the temperature range of the martensitic transformation.},
doi = {doi:10.1117/12.484689},
gsid = {5774356074785500281},
keywords = {NiMnGa, magnetostrykcja, efekt pamięci kształtu}
}