Magnetoelastic stresses in epitaxial (110) Terfenol-D thin films

Method for Detecting Defects in Silicon-On-Insulator Using Capacitance Transient Spectroscopy

“…We also see that the deformations within the (110) plane (y zplane in figure 1) are different, zz = yy , unlike the XRD results at zero-field, which indicate that they are isotropic, zz = yy . The shear deformations within the (110) plane, yz , cannot be compared with the XRD results; however, they are small, except at 140 K. The reason for the differences found between our values for the strains, obtained under a magnetic field, and the XRD zero-field values can be ascribed to the magnetostriction, which is large due to the strong magnetoelastic coupling in this system [7]. For instance, at 2 T the magnetization ea at 140 K is [111], and the large magnetostriction must be the origin of the large shear strain, yz , obtained at this temperature; as to the non-shear strains, at 40 K, where the magnetization ea is [001] and the magnetostriction is larger, we obtain a high value for the zz strain; whereas at RT the magnetization ea is [110], because at this temperature the magnetostriction is small [7], and the strain yy is not very different from the zero-field value.…”

“…In this situation, it is a customary procedure to extrapolate the anisotropy constants to infinite field linearly, especially when the anisotropy fields at different temperatures are of the same order or smaller than the applied fields. In our case, magnetization hysteresis loops indicate that the anisotropy fields are below 1.5 T [7]. Therefore, we have proceeded with such an extrapolation to get the true anisotropy constants (see figure 4, for the RT case).…”

“…In previous works, we have studied the magnetic and MEL properties of some REFe 2 thin-films (RE = Tb, Tb 0.3 Dy 0.7 ) [6,7]. Clear effects of epitaxial strain and interfaces on the magnetoelastic coupling were shown.…”

“…The four maxima and four minima found determine the angular positions of Free energy density (MPa) Figure 5. Contour plot of isoenergy lines at RT by using the b 1 and b 2 magnetoelastic stress parameters [7], the zero-field strains measured by x-rays [5], and the anisotropy constants from . There is some discrepancy between the directions obtained by us and those deduced from Mössbauer data but, qualitatively, both coincide in the fact that the magnetization rotates towards the plane of the film on increasing the temperature.…”

Influence of grain morphology and orientation on saturation magnetostriction of polycrystalline Terfenol-D

“…In this work we study Terfenol-D at room temperature. For the elastic constants we set the values given by Clark [10,14] [16], so that we set the isotropic magnetostrictive coefficient to zero (λ α = 0). The magnetocrystalline anisotropy constants vary significantly, depending on temperature and stoichiometry [2,14,16,17].…”