Epitaxial Ni-Mn-Ga-Co thin films on PMN-PT substrates for multicaloric applications

Journal Article · Fri Aug 07 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4927850· OSTI ID:22494686

Niemann, R.; Schultz, L.; Fähler, S. ^[1]; Diestel, A.; Hühne, R. ^[1]

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1. IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany)

Multicaloric stacks consisting of a magnetocaloric film on a piezoelectric substrate promise improved caloric properties as the transition temperature can be controlled by both magnetic and electric fields. We present epitaxially grown magnetocaloric Ni-Mn-Ga-Co thin films on ferroelectric Pb(Mg{sub 1/3}Nb{sub 2/3}){sub 0.72}Ti{sub 0.28}O{sub 3} substrates. Structure and microstructure of two samples, being in the austenitic and martensitic state at room temperature, are investigated by X-ray diffraction in two- and four-circle geometry and by atomic force microscopy. In addition, high temperature magnetometry was performed on the latter sample. The combination of these methods allows separating the influence of epitaxial growth and martensitic transformation. A preferential alignment of twin boundaries is observed already in the as-deposited state, which indicates the presence of prestress, without applying an electric field to the substrate. A temperature-magnetic field phase diagram is presented, which demonstrates the inverse magnetocaloric effect of the epitaxial Ni-Mn-Ga-Co film.

• OSTI ID: 22494686
• Journal Information: Journal of Applied Physics, Vol. 118, Issue 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOMIC FORCE MICROSCOPY
AUSTENITIC STEELS
ELECTRIC FIELDS
EPITAXY
FERROELECTRIC MATERIALS
MAGNETIC FIELDS
MAGNETIC PROPERTIES
MARTENSITIC STEELS
MICROSTRUCTURE
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PIEZOELECTRICITY
SUBSTRATES
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THIN FILMS
TRANSITION TEMPERATURE
X-RAY DIFFRACTION