Piezomagnetic Performance of Stress-Annealed FeAlB Alloys

Author(s)

Bormio-Nunes, Cristina ^[1] ; de Souza Dias, Mateus Botani ^[1]

Affiliation

^[1] Univ Sao Paulo, Escola Engn Lorena, BR-12602810 Lorena - Brazil

• Document type: Journal article
• Source: IEEE Transactions on Magnetics; v. 53, n. 11 NOV 2017.
• Web of Science Citations: 1

Abstract

Two FeAlB polycrystalline alloys were stress annealed and had the piezomagnetic behavior determined before and after the stress annealing (SA). The concentration of boron is constant, 1.6% (at%). The alloys are basically formed by the phase Fe2B dispersed in a bcc matrix. The bcc matrix can be formed of a disordered and/or ordered structure, depending on ratio of Fe: Al, that was fixed as 86Fe: 14Al and 80Fe: 20Al. Magnetostriction and magnetic induction were measured as a function of magnetic field and compressive stresses. The piezomagnetic coefficient d lambda equivalent to d lambda/dH improvement due to SA was achieved, in which. is the magnetostriction and H the applied magnetic field. SA causes the reorientation of the magnetic moment of the material creating an artificial magnetic anisotropy. The behavior of the coefficient d(33) varies due to changes in Al content, since the magnetocrystalline anisotropy of the alloy depends on the ordering of the bcc matrix. Values of d(33) up to 4 nm/A were reached for the polycrystalline alloy with 14% Al (at%) in an interval of compressive stresses of 0 <= | sigma| <= 177 MPa. This large interval of compression stress is due to the presence of the Fe2B phase. (AU)

• FAPESP's process: 14/16872-0 - Optimization of the piezomagnetic properties of Fe-Al-B alloys for use in the force sensors
• Grantee: Mateus Botani de Souza Dias
• Support Opportunities: Scholarships in Brazil - Doctorate