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1

Week interlayer exchange coupling in Fe-Zr and Fe-Ti layered structures

Smardz L., Smardz K.

Materials Science Poland

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2006

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Vol. 24, No. 3

821--826

EN

20nm-Fe/dZr-Zr/20nm-Fe and 20nm-Fe/dTi-Ti/20nm-Fe trilayers with wedged Zr and Ti sublayers were prepared at room temperature using UHV (5 × 10-10 mbar) RF/DC magnetron sputtering. Results showed that the Fe sublayers are ferromagnetically coupled up to Zr and Ti spacer thickness of about 1.5 and 2 nm, respectively. Furthermore, a weak antiferromagnetic (ferromagnetic) coupling of the Fe sublayers was observed for a Zr (Ti) thickness range between 1.5 and 3 nm (2 and 3.4 nm). The Fe sublayers are very weakly exchange coupled or decoupled for dZr > 3 nm and dTi > 3.4 nm. The small decoupling Ti and Zr thickness could be explained by spontaneous formation of a quasi-amorphous structure of the paramagnetic spacer during the deposition process.

2

The influence of Ge on antiferromagnetic coupling in Fe/Si multilayers

Wandziuk P., Luciński T., Kopcewicz M.

Materials Science Poland

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2006

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Vol. 24, No. 3

861--865

EN

The magnetic and structural properties of sputtered Fe/Ge, Fe/Ge/Si/Ge and Fe/Si/Ge/Si multilayers were studied. Magnetization measurements revealed the absence of antiferromagnetic coupling for Ge spacer. It was found that during the multilayer deposition a 0.5 nm thick Fe layer at each Fe/Ge interface became nonferromagnetic leading to formation of antiferromagnetic structures. Mössbauer spectra showed the existance of ferro- and/or antiferromagnetic structures at Fe/Ge interfaces, and ferromagnetic and paramagnetic structures at Fe/Si interfaces. We have found that substitution of Si by at least 0.5 nm of Ge in the 1.1 nm thick Si spacer led to disappearance of antiferromagnetic coupling in the Fe/Si multilayers.

3

Temperature dependence of magnetization reversal in Ni80Fe20/Au/Co/Au multilayers

Szymański B., Stobiecki F., Urbaniak M.

Materials Science Poland

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2006

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Vol. 24, No. 3

849--853

EN

In this contribution we present the results concerning temperature changes of magnetic properties of [Ni80Fe20(2 nm)/Au(tAu)/Co(tCo)/Au(tAu)]10 multilayers (MLs) with tAu = 1.5, 2.2 nm and tCo = 0.6, 0.8 nm. Hysteresis loops of investigated MLs were measured using vibrating sample magnetometer in temperature range from 175 to 423 K. Saturation field HSCo of Co layers, determined from the loops taken with in-plane applied field, increases with decreasing temperature. The HSCo field is directly related to perpendicular magnetic anisotropy of Co layer. It was also found that a shape of a central part of the hysteresis loops, taken with magnetic field applied perpendicular to the sample plane, is characteristic for samples with large perpendicular anisotropy and stripe domain structure. The shape of hysteresis loops is preserved in the whole temperature range of measurements indicating a presence of stable stripe domains. The magnetization reversal of the Co layers can be described by nucleation HN, annihilation HA and coercive HC fields. Temperature dependence of above mentioned parameters is presented.

4

Structure and electronic properties of Fe-Ti thin films

Smardz K., Smardz L.

Materials Science Poland

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2006

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Vol. 24, No. 3

827--831

EN

Fe/Ti multilayers (MLs) prepared onto glass substrates using UHV RF/DC magnetron sputtering. Results showed a significant drop of the coercivity measured for the Fe/Ti MLs with decrease in Fe layer thickness - typically from Hc ~ 2.2 kA/m to Hc ~ 0.2 kA/m - observed at a critical Fe thickness dcrit ~ 2.3 nm. Structural studies showed that the deposition of the 0.18 nm - Fe / 0.22 nm - Ti ML at 285 K leads to the formation of an uniform amorphous Fe-Ti alloy thin film due to a strong interdiffusion during the growth process. On the other hand, in-situ annealing of this ML at 750 K for 2 h resulted in the creation of a nanocrystalline phase. Furthermore, in-situ XPS studies showed that the valence band of the nanocrystalline Fe-Ti alloy film is broader compared to that measured for the amorphous phase with the same average composition.

5

Ni80Fe20/Au/Co/Au multilayers as magnetic field sensors

Stobiecki F., Urbaniak M., Szymański B., Luciński T., Schmidt M., Aleksiejew J.

Materials Science Poland

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2006

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Vol. 24, No. 3

833--838

EN

Sputter deposited (Ni80Fe20/Au/Co/Au)N multilayers characterized by alternating easy-plane (Permalloy) and perpendicular (cobalt) anisotropy were investigated. Such films can be used as GMR sensors with linear R(H) dependence in a broad range of magnetic fields. The influence of NiFe, Au, Co layers thickness and repetition number N on GMR effect is discussed. We optimized the multilayer parameters for the application purposes.