Magnetic phase transitions, magnetocrystalline anisotropy, and crystal-field interactions in theRFe11Ti series (whereR=Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, or Tm)

Magnetic and Mössbauer spectral study of ErFe11Ti and ErFe11TiH

“…2 by the closed symbols, both the real and imaginary parts of the ac susceptibility of ErFe 11 Ti exhibit sharp peaks at 50 K, peaks which are undoubtedly assigned to the spin reorientation observed at this temperature. Indeed, in ErFe 11 Ti, the easy magnetization direction is known 18 to change from parallel to the c axis above 50 K to canted from the c axis below 50 K. Because in the RFe 11 Ti structure, the iron sublattices favor a uniaxial magnetic anisotropy parallel to the c axis and erbium, like samarium, has a positive second-order Stevens coefficient, ␣ J , which reinforces the uniaxial magnetic anisotropy, ErFe 11 Ti would be expected to maintain this uniaxial anisotropy at all temperatures. However, the sixth-order crystal-field term is particularly important for erbium because of its large positive Stevens coefficient, ␥ J .…”

“…The spin-reorientation temperature was determined from the anomaly in the temperature dependence of the ac magnetic susceptibility, a technique which is known 18,31 to be very sensitive to changes in the magnetization direction in rare-earth transition-metal intermetallic compounds. As is shown in Fig.…”

“…Hence, below the spin-reorientation temperature, the Mössbauer spectra of ErFe 11 TiH are modeled with 15 sextets, which involve 26 hyperfine parameters, one linewidth, and one total absorption area. In contrast, in the case of ErFe 11 Ti, for which the canting angle 18 of the moments from the c axis is small at only ϳ20°, the further subdivision of the 8i and 8j sextets was not necessary in order to obtain good fits below the spin reorientation. The fits below the spin reorientation, as may be seen in Figs.…”

Domain-wall dynamics in aligned boundSm2Fe17

“…9 ͑v͒ Many materials show an asymmetic Ј(T) peak followed by a rise in Ј and a Љ peak. [9][10][11][12][13][14][15] An extensive review on this subject was recently made in Ref. 16, which concluded that the physical origin of the anomalies remained unclear, although various interpretations had been proposed in the literature.…”

“…Thus, different types of anomalous temperature dependence of ac have been reported in the literature for these materials. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] ac is considered anomalous when a relation to K i cannot be found, even after classical technical magnetization theories for DWD susceptibility have been taken into account. In Ref.…”