Title: Magnetostrictive materials and method for improving AC characteristics in same

Abstract

The present invention provides Terfenol-D alloys ("doped" Terfenol) having optimized performances under the condition of time-dependent magnetic fields. In one embodiment, performance is optimized by lowering the conductivity of Terfenol, thereby improving the frequency response. This can be achieved through addition of Group III or IV elements, such as Si and Al. Addition of these types of elements provides scattering sites for conduction electrons, thereby increasing resistivity by 125% which leads to an average increase in penetration depth of 80% at 1 kHz and an increase in energy conversion efficiency of 55%. The permeability of doped Terfenol remains constant over a wider frequency range as compared with undoped Terfenol. These results demonstrate that adding impurities, such as Si and Al, are effective in improving the ac characteristics of Terfenol. A magnetoelastic Gruneisen parameter, .gamma..sub.me, has also been derived from the thermodynamic equations of state, and provides another means by which to characterize the coupling efficiency in magnetostrictive materials on a more fundamental basis.

Inventors:

Pulvirenti, Patricia P ^[1]; Jiles, David C ^[2]

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1. Chicago, IL
2. Ames, IA

Issue Date:

Mon Jan 01 00:00:00 EST 2001

Research Org.:

Ames Laboratory (AMES), Ames, IA; Iowa State Univ., Ames, IA (United States)

OSTI Identifier:

873927

Patent Number(s):

6273965

Application Number:

08/953,192

Assignee:

Iowa State University Research Foundation, Inc. (Ames, IA)

Patent Classifications (CPCs):

H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01F - MAGNETS

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H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01F - MAGNETS

H01F1/0306 - {Metals or alloys, e.g. LAVES phase alloys of the MgCu2-type

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DOE Contract Number:  

W-7405-ENG-82

Resource Type:

Patent

Country of Publication:

United States

Language:

English

Subject:

magnetostrictive; materials; method; improving; characteristics; provides; terfenol-d; alloys; doped; terfenol; optimized; performances; condition; time-dependent; magnetic; fields; embodiment; performance; lowering; conductivity; frequency; response; achieved; addition; iii; elements; types; scattering; sites; conduction; electrons; increasing; resistivity; 125; leads; average; increase; penetration; depth; 80; khz; energy; conversion; efficiency; 55; permeability; remains; constant; wider; range; compared; undoped; results; demonstrate; adding; impurities; effective; magnetoelastic; gruneisen; parameter; gamma; derived; thermodynamic; equations; means; characterize; coupling; fundamental; basis; conversion efficiency; magnetic field; magnetic fields; energy conversion; frequency range; remains constant; penetration depth; coupling efficiency; magnetostrictive materials; magnetostrictive material; frequency response; conduction electrons; adding impurities; /148/420/