Huge magnetostriction in Tb3Fe5O12, Dy3Fe5O12, Ho3Fe5O12, Er3Fe5O12 garnets

Large-Pore Mesoporous Ho3Fe5O12 Thin Films with a Strong Room-Temperature Perpendicular Magnetic Anisotropy by Sol–Gel Processing

“…From these curves, it can be seen that (1) the ZFC data are similar for both film orientations or, in other words, field directions, while the FC data differ from each other below ~150 K, (2) the films exhibit no typical signs of superparamagnetism, and (3) the Curie temperature, T C ≈ 550 K, at which the material loses its magnetic order is in the range reported in the literature (545 K ≤ T C ≤ 567 K). [53][54][55][56] Overall, the ZFC data show that the sol-gel derived material starts off with a low moment and magnetization increases as the temperature is increased until a maximum is reached at (41 ± 2) K. The origin of this maximum is at present unknown, but might be associated with either some kind of spin orientation rearrangement or magnetic domain rearrangement. However, other factors might play a role as well, including film geometry and competition between sublattice exchange parameters.…”

“…The average maximum strain ε is 0.17%. Given that HoIG has negative λ 111 and λ 100 magnetostriction constants, 53 such lattice distortions force the easy axis for magnetic alignment (along the [111] crystallographic direction in garnets) to lie perpendicular to the tension direction, as reported for strained epitaxial garnet thin films. 37 We presume that the preference for magnetization in the out-of-plane direction stems from a similar strain anisotropy that overcomes the strong shape anisotropy of the thin films.…”

Far-infrared spectra of the magnetic exchange resonances and optical phonons and their connection to magnetic and dielectric properties of Dy3Fe5OKang1, Standard2, Rogers3 et al. 2012Phys. Rev. B17150View full textAdd to dashboardCite

“…This splitting is most likely related to the rhombohedral distortion of the garnet lattice that appears in the same temperature range. 21 In Section VI we will discuss similar changes in the spectra of optical phonons, which are induced by the same rhombohedral distortion. The weak and broad absorption line at 42 cm -1 appears for T> 20 K and is probably due to the optical transition between the excited CF levels, such as CF1 and CF3.…”

“…21,22,23 At room temperature Figure 1(a) where the compensation point at T com =223 K is marked with an arrow. Below 100 K, a rhombohedral distortion of the cubic cell causes the canting of Dy spins, which is described as a "double umbrella structure".…”

“…12(b)] reported previously for Dy-IG in the same temperature range. 21 Calculations of the temperature dependence of the E phonon frequency has been done using the following equation 37…”