TY - GEN
T1 - Structure of Ni-Mn-Ga films prepared by sputtering method
AU - Ohtsuka, Makoto
AU - Chiba, Kouki
AU - Matsumoto, Minoru
AU - Itagaki, Kimio
PY - 2000/12/1
Y1 - 2000/12/1
N2 - The properties of Ni-Mn-Ga films such as chemical composition, crystal structure, microstructure and transformation temperature were investigated with respect to sputtering conditions in the present study. The Ni-Mn-Ga films were deposited on a polyvinyl alcohol substrate with a radio-frequency magnetron sputtering apparatus using the Ni50Mn25Ga25 and Ni52Mn24Ga24 targets. After separating from the substrates, the films were annealed at the temperature between 873 and 1273 K for 3.6 ks. The chemical composition of the films depended on the radio-frequency generating power, however, there was no dependence on the heat treatment temperature. Each deposited film had a columnar grain structure. After heat treatment, the width of columnar grains widened and then became indistinct with increasing heat treatment temperature. The Heusler type cubic crystal structure of the film with heat treatment at 1073 K changed to the tetragonal one through the martensitic structural transformation during cooling. The martensitic structural transformation temperature increased with increasing nickel content of films, while the Curie temperature decreased. The film obtained at 200 W using the Ni52Mn24Ga24 target after heat treatment at 1073 K showed one-way shape memory effect through the reverse martensitic structural transformation during heating.
AB - The properties of Ni-Mn-Ga films such as chemical composition, crystal structure, microstructure and transformation temperature were investigated with respect to sputtering conditions in the present study. The Ni-Mn-Ga films were deposited on a polyvinyl alcohol substrate with a radio-frequency magnetron sputtering apparatus using the Ni50Mn25Ga25 and Ni52Mn24Ga24 targets. After separating from the substrates, the films were annealed at the temperature between 873 and 1273 K for 3.6 ks. The chemical composition of the films depended on the radio-frequency generating power, however, there was no dependence on the heat treatment temperature. Each deposited film had a columnar grain structure. After heat treatment, the width of columnar grains widened and then became indistinct with increasing heat treatment temperature. The Heusler type cubic crystal structure of the film with heat treatment at 1073 K changed to the tetragonal one through the martensitic structural transformation during cooling. The martensitic structural transformation temperature increased with increasing nickel content of films, while the Curie temperature decreased. The film obtained at 200 W using the Ni52Mn24Ga24 target after heat treatment at 1073 K showed one-way shape memory effect through the reverse martensitic structural transformation during heating.
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M3 - Conference contribution
AN - SCOPUS:0034592534
SN - 087339495X
T3 - Proceedings of the Second International Conference on Processing Materials for Properties
SP - 301
EP - 306
BT - Proceedings of the Second International Conference on Processing Materials for Properties
A2 - Mishra, B.
A2 - Yamauchi, C,
A2 - Mishra, B.
A2 - Yamauchi, C.
T2 - Proceedings of the Second International Conference on Processing Materials for Properties
Y2 - 5 November 2000 through 8 November 2000
ER -