Magnetic and structural properties of Lu2(Fe, Mn)17Hy hydrides
The Lu2Fe17−xMnxHy, x = 0–2, y = 0–3, hydrides with the Th2Ni17-type crystal structure were prepared and their structural and magnetic parameters were studied. The lattice parameters measured at room temperature increase smoothly with H content. The magnetic measurements indicate that the Lu2Fe17Hy hydrides (with y up to 1.77) are antiferromagnets at high temperatures and ferromagnets at low temperatures. The Lu2Fe16.5Mn0.5 compound also has a high temperature antiferromagnetic state, but its hydrides are ferromagnets only. The Lu2Fe17−xMnxHy hydrides, with x = 0.7 and 2, are ferromagnets with Tc monotonically increasing with H content. The saturation magnetization measured for Lu2Fe17−xMnxHy, (x = 0,0.5,0.7,2 and 0
Magnetocrystalline anisotropy of R2Fe17Hx (x=0, 3) single crystals
Abstract The magnetocrystalline anisotropy of R 2 Fe 17 (R=Y, Gd, Tb, Ho and Er) and their hydrides are studied by analyzing the magnetization curves of single crystal samples in the temperature range 4.2–300 K in magnetic fields up to 140 kOe. There is no noticeable influence of hydrogenation on the magnetic anisotropy in the Y 2 Fe 17 and Gd 2 Fe 17 compounds. An easy-plane to easy-cone transition is detected for a Tb 2 Fe 17 H 3 single crystal after hydrogenation. A significant change of the magnetization process has been observed in the hydrides Ho 2 Fe 17 H 3 and Er 2 Fe 17 H 3 . Hydrogenation induces a FOMP-type transition in the Ho 2 Fe 17 H 3 compound and, on the contrary, leads to the disappearance of the FOMP type transition in the Er 2 Fe 17 H 3 compound. The obtained results are discussed on the basis of a model based on the interaction of the quadrupolar moment and the magnetic moment of the 4f electron shell of the rare earth ion with the interstitial hydrogen. It is established that the orientation of the quadrupolar moment of the asymmetric 4f shell with respect to the direction of the resulting magnetic moment of 4f electrons plays an important role.
Researches on Structural Factor Involvement in Oral Tribology
This study is focused on two ceramic materials, D.SING (Ivoclar) and VM13 (emphasis the VITA TN), frequently used in restorative dentistry practice and it comes to complete a full set of results obtained by the authors over several years of research on oral tribology with main influence on oral health. In this way there are involved more specific structural aspects of dental restorative ceramic materials quality as is shown in [1].