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MA: Fachverband Magnetismus

MA 9: Magnetic Materials I

MA 9.5: Talk

Monday, March 14, 2011, 15:45–16:00, HSZ 401

The effect of boron doping on the magnetostriction of Fe-Ga and Fe-Al samples — •Mathias Doerr¹, Claudio Teodoro dos Santos², Sergey Granovsky¹, Cristina Bormio-Nunes², and Michael Loewenhaupt¹ — ¹TU Dresden, Institut für Festkörperphysik, D-01062 Dresden, Germany. — ²Universidade de Sao Paulo, Escola de Engenharia de Lorena, CA 116 CEP 12602-810 Lorena, Brazil.

Fe-Ga (Galfenol) based alloys are used in a number of magnetomechanical applications because of the high magnetostriction values of more than 100 ppm at room temperature. The addition of boron inhibits the crystallographic ordering of the alloys and stabilizes the disordered A2 structure that is responsible for the high striction values. Especially, polycrystalline and rapid cooled Fe-Ga-B and Fe-Al-B samples were investigated in our project. Magnetization and longitudinal as well as transversal magnetostriction measurements at temperatures of 5K, 80K and 300K show a similar effect of the amount of B as found on single crystals. Whereas the saturation magnetization is nearly the same and mainly determined by the Fe content, a dependence of the striction values on the amount of B is visible (more than 10% in the Fe-Al system). The results illustrate the influence of the stoichiometry and the preparation conditions on the magnetomechanical properties.