Magnetization Studies on Tb-Fe and Tb-Fe-Co Thin Films
TL;DR: Magnetization studies were carried out on TbFe and Tb-Fe-Co thin films, prepared using magnetron co-sputtering technique as discussed by the authors, and all the films were observed to exhibit planar anisotropy at 25 K.
Abstract: Magnetization studies were carried out on Tb-Fe and Tb-Fe-Co thin films, prepared using magnetron co-sputtering technique. The films Tb
25
Fe
75 and Tb
31
Fe
69 were found to have perpendicular magnetic anisotropy (PMA) both at 25 and 300 K. In Tb-Fe-Co films, all the films were observed to exhibit planar anisotropy at 25 K, due to the increase of strain-induced anisotropy as a result of large magnetostriction at low temperatures leading to the development of in-plane anisotropy. PMA was observed in the films Tb
35
Fe
37
Co
28
, Tb
56
Fe
25
Co
19
, and Tb
63
Fe
20
Co
17 at 300 K. The Curie temperatures (T
C ) of both TbxFe
100-x and Tb-Fe-Co films were found to be above room temperature (RT). Observing the Curie temperatures well above the RT, with the existence of PMA at RTs, is an interesting object in these films to find in magnetic data storage applications.
Citations
More filters
01 Jan 1996
1 citations
References
More filters
TL;DR: Sputter-deposited magnetostrictive films present a new and interesting approach to realizing cantilever and membrane-type actuators or resonant sensors in microsystems as they offer features like contactless, high frequency operation, simple actuator designs and a cost-effective manufacturing technique as discussed by the authors.
69 citations
Additional excerpts
...plane, the magnetostriction reduced substantially [9]....
[...]
TL;DR: In this paper, the Hall effect in amorphous films in the ternary ferrimagnetic systems Co−Gd−Mo and Co•Gd•Au was studied and the Hall coefficient was attributed to a combined effect of a negative Gd and a positive Co Hall coefficient.
Abstract: Amorphous magnetic alloys have unusually large extraordinary Hall coefficients (Rs) defined by the ratio of the Hall resistivity to the net magnetic moment of the alloy. We have studied the Hall effect in amorphous films in the ternary ferrimagnetic systems Co‐Gd‐Mo and Co‐Gd‐Au, alloys which exhibit compensation temperatures (Tcomp). Above Tcomp the Hall coefficient Rs is positive and below Tcomp the sign of Rs changes to negative in a discontinuous manner, probably limited by the homogeneity of the sample. We have also prepared amorphous Gd‐Au and Y‐Co films and measured Rs which we use to qualitatively separate the effects of the Co and Gd sublattices in the ternary alloys. We attribute the sign of Rs to a combined effect of a negative Gd and a positive Co Hall coefficient. Above Tcomp the Co is dominant and points in the direction of the applied field H while Gd is antiparallel to H. Thus, both sublattices contribute in a positive sense to Rs. Below Tcomp the Gd moment is dominant and the sign of Rs i...
65 citations
"Magnetization Studies on Tb-Fe and ..." refers background in this paper
...[10] have reported that the rate of change of magnetization in R-Fe films (with near compensation composition) was associated with the rare-earth anisotropy below the compensation temperature....
[...]
TL;DR: In this paper, the anisotropy constants of iron were determined from torque measurements on a {100} single-crystal disk in fields up to 15 000 oersteds or higher and at temperatures of 77, 195, and 300\ifmmode^\circ\else\textdegree\fi{}K.
Abstract: The anisotropy constants of iron have been determined from torque measurements on a {100} single-crystal disk in fields up to 15 000 oersteds or higher and at temperatures of 77, 195, and 300\ifmmode^\circ\else\textdegree\fi{}K. The values of ${K}_{1}$ at the three temperatures are (520\ifmmode\pm\else\textpm\fi{}10)\ifmmode\times\else\texttimes\fi{}${10}^{3}$, (505\ifmmode\pm\else\textpm\fi{}10)\ifmmode\times\else\texttimes\fi{}${10}^{3}$, and (480\ifmmode\pm\else\textpm\fi{}10)\ifmmode\times\else\texttimes\fi{}${10}^{3}$ ergs/${\mathrm{cm}}^{3}$; the value of ${K}_{2}$ at all three temperatures is (0\ifmmode\pm\else\textpm\fi{}50)\ifmmode\times\else\texttimes\fi{}${10}^{3}$ ergs/${\mathrm{cm}}^{3}$. The anisotropy decreases as the fourth power of the saturation magnetization over the temperature range studied.
62 citations
TL;DR: In this article, the singularity in the magnetization curve is transformed in the case of a polycrystalline specimen, and it is demonstrated that the singular point detection theory can be extended to first-order magnetization processes (FOMP), thus allowing extremely clear and accurate measurements of critical fields.
Abstract: Ferromagnetic crystals can show discontinuous jumps in the magnetization curve for certain combinations of the anisotropy constants. These are called first‐order magnetization processes (FOMP) and have been recently observed in a large variety of compounds. We analyze the problem of how this singularity in the magnetization curve is transformed in the case of a polycrystalline specimen. The problem is the same as that of the singular point detection theory (SPD) that was originally concerned with the singularities of the anisotropy fields and with the way of enhancing them. SPD is now a widely used method for measuring anisotropy fields. In the present work it is demonstrated that SPD can be extended to FOMP, thus allowing extremely clear and accurate measurements of critical fields using polycrystalline specimens. This provides in principle a powerful method for deep investigations in the anisotropy properties of ferromagnetic and ferrimagnetic materials. In Sec. II we examine how the critical parameters...
53 citations
"Magnetization Studies on Tb-Fe and ..." refers background in this paper
...This is a signature of possible first-order magnetization process when the anisotropy is large and localized [11]....
[...]
TL;DR: In this paper, the magnetostrictive behavior of amorphous thin films was studied by measuring the stress derivative of the perpendicular anisotropy, and large values of magnetostriction were found, of order 10 − 3, about the same as the value observed in their polycrystalline counterparts.
Abstract: The magnetostrictive behavior of amorphous ${\mathrm{Tb}}_{\mathit{x}}$${\mathrm{Fe}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ (0.10x0.45) thin films was studied by measuring the stress derivative of the perpendicular anisotropy. Large values of the magnetostriction were found, of order ${10}^{\mathrm{\ensuremath{-}}3}$, about the same as the value observed in their polycrystalline counterparts. Within this composition range, ${\mathrm{Tb}}_{45}$${\mathrm{Fe}}_{55}$ shows a large magnetostriction with a relatively low anisotropy which makes it a good candidate for application as a magnetoelastic element. After annealing at low temperature (175 \ifmmode^\circ\else\textdegree\fi{}C), relaxation of both perpendicular anisotropy and magnetostriction was observed. However, the relaxation strength was particularly remarkable in the range of low Tb content (x0.30). The relaxation behavior seems to indicate that local anelastic strain may be the origin of this bond anisotropy for low Tb content while additional structural anisotropy is likely to be responsible for the anisotropy in higher Tb content films.
46 citations
"Magnetization Studies on Tb-Fe and ..." refers background in this paper
...5 kOe, the curves are linear due to the large magnetostriction, since Tb–Fe films are known to possess large magnetostriction values [8]....
[...]
...In the Tb12Fe46Co42 film, the magnetization curve in the in-plane configuration exhibits a clear knee point and the magnetization after the knee point is seen to increase with increasing field without any tendency for saturation, possibly as a result of large magnetostriction [8]....
[...]