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## Full-Text Articles in Physics

Enhanced Differential Magnetostrictive Response In Annealed Terfenol‐D, N. Galloway, M. P. Schulze, R. D. Greenough, David C. Jiles

#### Enhanced Differential Magnetostrictive Response In Annealed Terfenol‐D, N. Galloway, M. P. Schulze, R. D. Greenough, David C. Jiles

*Ames Laboratory Publications*

The field and pressure dependencies of the magnetostriction of Tb_{0.316}Dy_{0.684}Fe_{1.982} have been measured in a grain‐oriented rod after thermally annealing for 1 day at 850 °C and for 4 days at 950 °C in an argon atmosphere. The results of the heat treatment are a fivefold increase in the strain coefficient *d* _{33}(=*d*λ/*dH*) and a 100% increase in the maximum strain (λ). There was also an increase in the λ‐vs‐*H*hysteresis. Under compressive uniaxial stress there was virtually no bulk change in magnetostrictive strain until the ...

A Model For Hysteretic Magnetic Properties Under The Application Of Noncoaxial Stress And Field, Martin J. Sablik, S. W. Rubin, L. A. Riley, David C. Jiles, David A. Kaminski, S. B. Biner

#### A Model For Hysteretic Magnetic Properties Under The Application Of Noncoaxial Stress And Field, Martin J. Sablik, S. W. Rubin, L. A. Riley, David C. Jiles, David A. Kaminski, S. B. Biner

*Center for Nondestructive Evaluation Publications*

Although descriptions of the effect of stress on spontaneous magnetization within a single domain already exist, there remains no adequate mathematical model for the effects of noncoaxial magnetic field and stress on bulk magnetization in a multidomained specimen. This article addresses the problem and provides a phenomenological theory that applies to the case of bulk isotropic materials. The magnetomechanical hysteresis model of Sablik and Jiles is thus extended to treat magnetic properties in the case of noncoaxial stress and magnetic field in an isotropic, polycrystalline medium. In the modeling, noncollinearity between magnetization and magnetic field is taken into account. The ...

Modeling Of Micromagnetic Barkhausen Activity Using A Stochastic Process Extension To The Theory Of Hysteresis, David C. Jiles, Levent B. Sipahi, G. Williams

#### Modeling Of Micromagnetic Barkhausen Activity Using A Stochastic Process Extension To The Theory Of Hysteresis, David C. Jiles, Levent B. Sipahi, G. Williams

*Materials Science and Engineering Publications*

Recent work by Bertotti [IEEE Trans. Magn. **MAG‐24**, 621 (1988)] and others has shown that it is possible to model the micromagnetic Barkhausen discontinuities at the coercive point using a two‐parameter stochastic model. However, the present formulation of the model is restricted to limited regions of the hysteresis curve over which *dM*/*dH* is approximately constant and when*dH*/*dt* is held at a constant rate. A natural extension of this model is to take the basic result, in which the level of Barkhausen activity in one time period is related to the activity in the previous time ...