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Notes: FeCoV/TiNx and FeCoV/Ti multilayers having tFeCoV=30–700 Å prepared by dc magnetron sputtering are investigated by x-ray diffraction, stress, and magnetization measurements. The x-ray diffraction data of the FeCoV/TiNx system show the presence of interstitial N atoms in the FeCoV layers due to reactive sputtering of Ti with nitrogen. The interstitial N causes an expansion of the FeCoV lattice in FeCoV/TiNx for small tFeCoV. However, for the samples with large tFeCoV, no lattice expansion is observed. In addition to the lattice expansion caused by the intake of N atoms, a change in the crystalline texture of FeCoV layers is also observed as indicated by the enhancement of the FeCoV(200) peaks. The magnetic hysteresis measurements on the samples show that the easy direction of magnetization lies in the plane of the layers. They further show that there are easy and hard axes of magnetization within the plane of the FeCoV layers. The stress anisotropy present in the plane of the samples induces a magnetic anisotropy through magnetostrictive effects leading to the formation of the in- plane easy axis. The hysteresis and stress measurements carried out on these samples clearly show the influence of N on the in-plane magnetic anisotropy. The magnetoelastic energy in the case of the FeCoV/TiNx system, calculated from the stress data and from the magnetization measurements as a function of tFeCoV is found to agree over a large range of thickness, whereas the curves deviate significantly for small layer thickness. This deviation may be due to the role of the FeCoVNx phase. Hysteresis measurements also show that the remanence is about 95% for all the samples of the FeCoV/TiNx system. In contrast, the coercivity increases linearly with increasing tFeCoV in this system. The coercivity of the FeCoV/Ti system is larger and increases more rapidly with tFeCoV, as compared with the FeCoV/TiNx system. This behavior is attributed to a smaller grain size in the FeCoV/TiNx system due to the reactive sputtering of the Ti layers. However, there is no significant influence of N on the saturation magnetization of both systems. © 2002 American Institute of Physics.

Notes: Cubic Laves phase alloys of Ho0.85Tb0.15Fe2−xNix (0≤x≤2) were prepared and the lattice parameters, evaluated as a function of x at room temperature, show deviation from Vegard's law. This was attributed to the presence of a magnetovolume effect and charge transfer. Magnetization measurements were performed in the temperature range 77–700 K. The results suggest that the system undergoes a gradual transition from ferri- to ferromagnetic with increasing x. This has been explained based on the 3d band model. Furthermore, a monotonic decrease in Curie temperature with x was observed. Electrical resistivity studies were carried out in the temperature range 16–700 K. An anomaly was found in the vicinity of the Curie temperature for x=2 which has been attributed to the existence of the long-range nature of the critical fluctuations due to short-range spin ordering.