Aplicação do efeito Mossbauer ao estudo de propriedades físicas do sistema ZrxTi1-xFe2 

• Ano de defesa: 1985
• Autor(a) principal: Ronaldo AlÍpio Mansur
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Física; Mossbauer; Fisica do estado solido; Efeito; Mossbauer, Efeito
• Link de acesso: http://hdl.handle.net/1843/BUOS-AAQNHY

Using Espectrospecopia Mossbaur and diffraction of X-rays, we studied the physical properties of ZrxTi1-xFe2.Foram pseudo-binary system prepared 15 samples at concentrations of 0.00 <x <1,00.As analysis of measurement results with both techniques show that the solubility of Zr in TiFe2 phase has a limit (41.5 + 1.5) at.%, while the solubility of Zr in ZrFe2 phase has a limit (19.5 + 1.5) at. % .Among these two limits, the phases Ti (Zr) and Fe 2 Zr (Fi) Fe2 coexist with fixed chemical compositions, determined by the limits of solubilidade.A phase Ti (Zr) Fe2 has two sites for the Fe atom. in a of them, named 2nd, Fe atoms are paramagnetic, while at the other site, called 6h, mating antiferromagnetically with the direction of easy magnetization along the c axis. The ratio of the population of these sites is 3: 1, and does not change with the substitution of Ti by Zr, while the split quadrupular remain constant; hyperfine field to the site 6h our results show an increase in the concentration of Zr to the saturation stage, when remains constant. This same behavior is observed for the Néel temperature, growing Tn = 275k (for TiFe2) to about 327k for the IT phase (ZR) saturada.A FE2 stage Zr (Ti) Fe2 is ferromagnetic and has two sites for Fe atoms, which are distinguished by the different orientations of the respective main axes of the electric field gradient in relation to the easy magnetization axis. While in binary phase Zr (Ti) Fe2 this reason decreases with increasing Zr concentration suggesting a change mentioned above or the orientation or the amount and direction of the electric field gradient. The isomeric shifts of both sites had no measurable variation with Zr concentration, probably due to difficulties in adjustment of Mossbuaer spectra, which makes it difficult to reach any conclusion about the variation of quadrupular split this stage, although the introduction of Ti the Network ZrFe2 suggest a tendency to decrease in the value of eQVzz. The hyperfine field and the Curie temperature decreased with increasing concentration of Ti.Os network parameters are in good agreement with the Vegard's Law in existence regions of each stage being constant in the presence of both region.