Transmission electron microscopy of Terfenol-D crystals

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.361693· OSTI ID:280004

Holden, A P; Lord, D G; Grundy, P J ^[1]

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1. Physics Department, Joule Laboratory, University of Salford, M54WT (United Kingdom)

Magnetic domain and microstructure observations are presented from samples of pseudo-single-crystal Terfenol-D examined by transmission electron microscopy (TEM). This ternary alloy is of significant technological interest since it exhibits the highest known magnetostriction to anisotropy ratio near room temperature. Specimens for TEM studies in (110), (111), and (112) orientations have also shown regions of unusual diffraction contrast in bright field which appears to be very sensitive to specimen tilt. Lorentz mode TEM has subsequently shown such regions to correspond exactly with magnetic domains. This contrast is attributed to the high magnetostrictive strain causing a local distortion of the lattice and thus a local deviation from the Bragg condition. This conclusion has been investigated and supported by TEM observations with the samples cooled below the spin reorientation temperature. When this transition is reached the diffraction contrast in bright field is considerably decreased and cannot be made to vary by tilting the specimen. The latter experiments also indicate that the change from {l_angle}111{r_angle} to {l_angle}100{r_angle} easy axis is not a well-defined one but, rather, that the spin reorientation is a sluggish change. High-resolution lattice images show the coherency of the twin boundaries. {copyright} {ital 1996 American Institute of Physics.}

• OSTI ID: 280004
• Report Number(s): CONF-951101--
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 79; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DOMAIN STRUCTURE
DYSPROSIUM COMPOUNDS
IRON COMPOUNDS
MAGNETIC MATERIALS
MICROSTRUCTURE
PHASE TRANSFORMATIONS
TERBIUM COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY
TWINNING