Laser processing of Tb0.3Dy0.7Fe1.92 films

dc.contributor.advisorKovar, Desiderioen
dc.creatorMa, Dat Truongen
dc.description.abstractIn the past decade, there has been an increased interest in magnetostrictive materials for micro actuators and sensors. Of particular importance are the Fe₂R intermetallics, where R = Tb, Dy. In this study, films of Tb[subscript 0.3]Dy[subscript 0.7]Fe[subscript 1.92] were prepared by three laser processing techniques (pulsed laser deposition, flat plate ablation and laser ablation of microparticles) to explore the effect of processing parameters on particle size, crystallinity and magnetic properties. The laser used in the experiments was a KrF laser with a 12 ns pulse width. Pulsed laser deposition of an alloyed target in vacuum produces dense amorphous films with the similar composition to the target, low coercivity (46 Oe) and good magnetostriction ([lambda][subcript two horizontal lines] = 305 ppm at 2300 Oe). Flat plate ablation and laser ablation of microparticles produced amorphous nanoparticles at 1 atm. The particles were subsequently jet deposited onto substrates to form thick films. Nanoparticle films produced by flat plate ablation resulted in oxidized and segregated particles due to extended, non-uniform plume expansion, laser target modification, and open porosity. Laser ablation of microparticles produced thick films with M[subscript s] = 13.8 emu/g. Two types of annealing treatments were performed to close porosity and increase Youngs modulus. Annealing of LAM films at temperatures up to 700°C in-situ and 950°C in a reducing atmosphere did not result in coarsening of the particles or crystallization of the Laves phase due to the core-shell structure of nanoparticles (rare earth oxide shell, Fe rich core) brought about by oxidation-induced segregation.en
dc.description.departmentMaterials Science and Engineeringen
dc.rightsCopyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.en
dc.subject.lcshLaser ablationen
dc.subject.lcshPulsed laser depositionen
dc.subject.lcshThick filmsen
dc.subject.lcshThin filmsen
dc.subject.lcshIron compoundsen
dc.subject.lcshIntermetallic compoundsen
dc.titleLaser processing of Tb0.3Dy0.7Fe1.92 filmsen
dc.type.genreThesisen Science and Engineeringen Science and Engineeringen University of Texas at Austinen of Philosophyen

Access full-text files

Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
17.16 MB
Adobe Portable Document Format

License bundle

Now showing 1 - 1 of 1
No Thumbnail Available
1.65 KB
Plain Text