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Focuses on a study which investigated a complex new magnetic refrigerant, suitable for the ideal Ericsson cycle. Properties that act as a magnetic refrigerant; Factor that answer the need for a highly efficient small cryocooler; Processes that compose the refrigeration cycle of the Carnot cycle.

A novel method is proposed for increasing the giant magnetoresistance (GMR) of dual spin valves of the CoFe/Cu/CoFe/Cu/CoFe type by inserting nano-oxide layers (NOLs) into the pinned layers. Using this method, MR ratio of 23.5% was obtained, a value equal to those of specular spin valves with antiferromagnetic oxide, e.g., NiO. This method allows the selection of metallic materials for the antiferromagnetic layer. In addition, we obtained the specularity factor of upper NOLs, 0.8, and that of lower NOLs, 0.7, by calculating Boltzmann equations taking into account the roughness of each interlayer. This model shows that the MR ratio would be 27.5% for dual spin valves with ideal NOLs. [Copyright &y& Elsevier]

We investigated current-perpendicular-to-plane (CPP) magnetotransport parameters of FexCo100-x/ Ag interfaces: interface specific resistance (ARF/N), extended interface resistance (AR* F/N), and spin scattering asymmetry (γ). We also investigated the dependence of interfacial parameters on the giant magnetoresistance effect with CPP geometry. For measuring these parameters, we prepared magnetic multilayers and pseudo spin valves (PSVs), combining the ferromagnetic (F) alloys Fe, Co, Fe50Co50, and Fe30Co70 with the nonmagnetic (N) metal Ag. In all cases, the largest ARF/N value was found to be ~0.68 mΩμm² with an enhanced AR* F/N value of ~1.9 mΩμm² for a (001)-oriented Fe/Ag interface, which suggests that spin-up and spin-down electrons on the Fermi surface have very different transmission probabilities. Such an interface can act as a spin filter through which only one type of electrons can pass. [ABSTRACT FROM AUTHOR]

Deposition and annealing behaviors of Al atoms on rough Cu (111) surface were investigated on the atomic scale by three-dimensional classical molecular dynamics simulation. The rough Cu surface was modeled by depositing 5 ML of Cu on Ta (011) substrate. Most Al atoms deposited on the rough Cu surface placed on the atomic steps, preserving the major features of the surface during Al deposition. This behavior was discussed in terms of the smaller barrier of the surface diffusion than Ehrlich–Schwoebel barrier of Al on Cu (111) surface. By annealing at 700 K, significant intermixing between Al and Cu rapidly occurs with decrease in the surface roughness. This behavior reveals that the exchange process of Al with substrate Cu dominates during the initial stage of high temperature annealing. [ABSTRACT FROM AUTHOR]

We have developed the FeCo nanocontact magnetoresistance (NCMR) with spin-valve structure [H. N. Fuke et al., IEEE Trans. Magn. 43, 2848 (2007)] which exhibits up to a MR ratio of 11%–12% at a resistance area (RA) of 0.3–0.55 Ω μm2. The nanocontact configurations were estimated at about 2 nm in in-plane diameter, 1.2 nm in thickness, and 0.55% in density for a RA∼0.5 Ω μm2 film based on in-plane current distribution by conductive atomic-force microscopy cross sectional transmission electron microscope images of the NCMR. The origin of the NCMR was discussed by comparing magnetic field dependence of resistance, with micromagnetics simulation based on the diffusive MR theory. It is found that our NCMR cannot be explained by diffusive domain wall theory or bulk scattering in free and pinned layers. It is likely that a theory on the basis of a ballistic MR consideration is needed to interpret our MR origin. [ABSTRACT FROM AUTHOR]

The current-perpendicular-to-plane (CPP) giant-magnetoresistance (GMR) of spin valves with Fe50Co50 alloy was investigated. It has been reported that the Cu inserted in Fe50Co50 is effective for enhancing CPP-GMR. In this paper, we investigated the number of Cu lamination effect on CPP-GMR and clarified that higher CPP-GMR is obtained by decreasing the number of Cu layers. In order to ascertain the reason for this tendency, the crystalline structure and magnetization were examined. As a result, it was found that the d spacing of Fe50Co50 increases when the number of Cu layers is increased, although saturation magnetization does not change. [ABSTRACT FROM AUTHOR]

In this work, we present a suitable material for metal-based spin-valve in current-perpendicular-to-plane (CPP) geometry. The AΔR (A is the element size and ΔR is the change in resistance) was investigated for three kinds of free and pinned layers material, that is, Co[sub 90]Fe[sub 10], Fe[sub 50]Co[sub 50], and Fe[sub 50]Co[sub 50] with half-atomic Cu layers. When the free and pinned layers are 5 nm, AΔR is 1.0 mΩ/µm², 1.6 mΩ µm², and 2.9 mΩ µm², respectively. Moreover, the dual-type spin valve having Fe[sub 50]Co[sub 50] with half-atomic Cu layers achieved 5.2 mΩ µm². According to the free and pinned layers thickness dependence of AΔR, the spin-dependent resistance at the interfaces between ferromagnetic layers and spacer Cu is enhanced mainly by changing from Co[sub 90]Fe[sub 10] to Fe[sub 50]Co[sub 50], and the spin-dependent bulk resistance in free and pinned layers is enlarged by inserting half-atomic Cu layers. [ABSTRACT FROM AUTHOR]

The concept of spin-filter spin-valve (SFSV) films is reviewed. The dependence of the free layer structure on the spin-filter effect was investigated by using model films and two types of free layers were compared, a single CoFe layer and a conventional NiFe/Co free layer. At the same magnetic thickness of the free layer, the SFSV films with a CoFe free layer showed a larger magnetoresistance (MR) ratio than those with a NiFe/Co free layer. This is partly attributed to the thinner CoFe free layer thickness, which is due to the fact that the CoFe free layer has higher B[sub s] than the NiFe/Co free layer. Moreover, SFSV films with a CoFe free layer still showed a larger MR ratio when the free layer thickness was the same. It suggests that other factors contribute to the high MR performance, such as the quality of the interface between a free layer and a high conductance layer. Film performance of MR 9% to 10%, ΔR[sub s] 1.5-2.0 Ω, H[sub c][sup ea]∼3 Oe, and λ[sub s]≤±0.5 ppm was obtained with a single CoFe free layer and synthetic antiferromagnetic pinned structure. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents an abstract of the study 'Influence of a Large Amount of Co Substitution on the Magnetic Properties of NdFeCoGaB Magnets,' by A. Tsutai, I. Sakai, M. Sahashi and K. Inomata.

We have investigated the microwave oscillations due to a spin transfer effect induced by direct current in ferromagnetic nanocontact magnetoresistive (NCMR) elements with a current-perpendicular-to-plane spin-valve structure consisting of an FeCo/FeCo–AlOx nano-oxide layer/FeCo multilayer for the reference/spacer/free layers, respectively. Characteristic microwave oscillations were observed in the NCMR elements at different magnetization states induced by the application of a spin-polarized current, which are considered to be related to the introduction of a ferromagnetic NC to spacer layer (large interlayer coupling) and the resonance concerning the stability of the magnetization states of the free and reference layers around the NCs. A marvelously narrow full width at half maximum (FWHM) of l0–20 MHz is observed under a high applied magnetic field where the reference layer magnetization is slightly off axis relative to the pinned direction. By contrast, a wider FWHM of 80–600 MHz is observed at the magnetization state where the magnetization of the free layer just aligned to the antiparallel configuration against the magnetization of the reference layer. These characteristic results are discussed in terms of a spin dynamics mechanism induced by spin transfer torque in the free and reference layers around NCs. [ABSTRACT FROM AUTHOR]

We have reported that body-centered-cubic (bcc) Fe[SUB50]Co[SUB50] with ultrathin Cu layers has large spin-dependent bulk scattering and enhances AΔR of spin valves. In order to clarify the role of Cu, two series of samples with (Fe[SUB50]Co[SUB50] (1 nm/Cu) × 5 were prepared by two different sputtering machines. Machine A has a high rate, and machine B has a comparatively low rate. Both of AΔR in series A and B are increased by inserting thin Cu of about 0.1 nm, but they have a significant difference in Cu thickness dependence. While series A keeps high AΔR through the Cu thickness, AΔR in series B decreases when Cu is thickened. In order to find the reason for the difference, we took the extended x-ray absorption structure (EXAFS) spectra. By comparing AΔR and EXAFS, it was found that the very thin Cu of about 0.1 nm in Fe[SUB50]Co[SUB50] takes a body-centered-cubic bcc structure, namely a solid solution state. Cu of 1 nm in spin valves with high AΔR takes a bcc and face-centered-cubic (fcc) evenly, and that with a low AΔR is a fcc structure. These results indicate that the existence of the solid solution Cu in Fe[SUB50]Co[SUB50] is attributable to the enhancement of AΔR and are consistent with the report that Cu impurity in Fe and Co enhances the difference between the subband resistivity of up and down spins. [ABSTRACT FROM AUTHOR]

To implement the specular nano-oxide-layer (NOL) spin valve (SV) heads for use in practical applications, it is key to simultaneously achieve a good specular effect of the NOL inserted in the synthetic ferrimagnet pinned layer (i.e., high magnetoresistance MR performance) and a strong pinning field through the NOL. By using CoFe+X as a substance to be subjected to oxidation, we obtained the NOL specular SV films simultaneously achieving a high MR ratio of 17%-18% and a high pinning field of 1100-1500 Oe. Narrow track (0.12 µm) heads were fabricated and they showed a high sensitivity of 10 mV/µm. Several reliability tests were done both at the sheet film level and the actual head level. The oxygen inside NOL was found to be stable up to 350 °C, and pinned layer magnetization canting after orthogonal field annealing was found to be almost the same as today's non-NOL SV films. An electrostatic discharge test and accelerated lifetime test were also performed and NOL specular heads were demonstrated to have almost the same robustness as today's non-NOL heads. [ABSTRACT FROM AUTHOR]

Three different techniques, natural oxidation, remote plasma oxidation and low energy ion beam oxidation, have been proved to be equally effective in forming nano-oxide layers (NOLs) in spin-valve films for specular enhancement of giant magnetoresistance (GMR) effect. GMR values over 12% have been routinely obtained in spin-valve films with NOL, corresponding to a 30% specular enhancement over those without NOL. The consistency and robustness of the oxidation processes has been demonstrated by a very large GMR value ∼19% in a dual spin-valve film with the NOLs formed in both pinned layers, the oscillatory dependence of the interlayer coupling field on Cu layer thickness in specular enhanced spin-valve films and the uniform and repeatable film performance over 5 in. substrates. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents a study which investigated the structural and magnetic properties of (R,Zr)(Fe,Co)[sub10](R=Nd,Sm) prepared by the rapid-quenching method. Influence of the presence of zirconium; Information on the saturation magnetization of crystals; Details of the magnetic hardening of the nitrogenated materials.

Presents information on a study which investigates spin-valve structures with a magnetic material buffer layer, CoNbZr (100 Å)/NiFe (20 Å), on an oxidized silicon substrate. Measurement of the magnetoresistance ratio; Crystal structure; Experimental and calculated x-ray diffraction profile; X-ray diffraction method.

Presents a study that examined the magnetic properties and magnetostriction in grain-oriented compounds. Experimental method; Results and discussions; Conclusion.

An epitaxial wurtzite (WZ) Mg0.23Zn0.77O barrier based magnetic tunnel junction (MTJ), with electrode-barrier structure of Co0.30Pt0.70 (111)/Mg0.23Zn0.77O (0001)/Co (0001), was fabricated. The good crystallinity and tunneling properties were experimentally confirmed. Electrical and magnetic investigations demonstrated its high resistance-area product of 1.05MXlm2, a maximum tunneling magneto-resistance (TMR) of 35.5%, and the existence of localized states within the tunneling barrier producing TMR rapid decrease and oscillation when increasing the applied bias voltage. The TMR value almost vanished at 200 K, which was attributed to the induced moment and strong spin-orbit coupling in Pt atoms at the Co0.30Pt0.70/Mg0.23Zn0.77O interface. Owing to the ferroelectric behavior in WZ-MgZnO materials, the fabrication of WZ-MgZnO barrier based MTJs deposited on a metallic ferromagnetic electrode will open routes for electrically controllable non-volatile devices that are compatible with CMOS technology. [ABSTRACT FROM AUTHOR]

We investigated the magnetoelectric properties of Cr2O3/Co all-thin-film exchange coupling system with Cr spacer layer. In this system, significantly small coercivity (Hc<50Oe) was obtained by the Cr spacer layer insertion between Cr2O3 and Co layers. Owing to the small Hc, exchange bias field, Hex, larger than Hc was achieved. It enabled us to observe magnetization switching at a zero magnetic field, when Hex was reversed by magnetoelectric effect of Cr2O3 layer. Finally, we demonstrated the isothermal magnetoelectric switching of magnetization in the Cr2O3/Cr/Co all-thin-film system. By changing the direction of the electric field during the isothermal magnetoelectric switching process, both Hex and magnetization at a zero magnetic field were reversed back and forth, i.e., isothermal magnetization switching by an electric field was achieved. [ABSTRACT FROM AUTHOR]

We clarify the origin of the interface perpendicular magnetic anisotropy (PMA) at the Cr2O3/ferromagnet interface by investigating the temperature dependence of the magnetic properties of Cr2O3/Co-Pt. We observed positive large interface PMA both above and below the blocking temperature of Cr2O3, with the PMA being less sensitive to temperature. Our results indicate that the effect of the metal/oxide interface, as well as that of the MgO/CoFeB interface, contributes strongly to the PMA at the Cr2O3/Co-Pt interface, although the effect of perpendicular exchange coupling might also slightly contribute to the interface PMA. [ABSTRACT FROM AUTHOR]

We have observed high exchange bias for a Cr2O3 film, which was crystallized from an amorphous Cr-oxide by annealing in O2 flow. To clarify the origin of the high exchange bias, we characterized the morphology of the Cr2O3 film. From X-ray diffraction, atomic force microscopy, and transmission electron microscopy measurements, we discovered that our polycrystalline Cr2O3 film was found to grow not to be entirely random orientation, but to form large R-planes on the surface. That is, R-planes were self-organized during crystallization. Since uncompensated Cr spins exist on R-planes of Cr2O3, the origin of the high exchange bias would be the self-organized R-planes. We successfully explained the peculiar temperature-dependent exchange bias and coercivity of the Cr2O3 film. For the Cr2O3 film, perpendicular exchange bias was obtained whereas out of plane direction is hard magnetization axis. This is because of the oblique Cr spin directions from out of plane direction of the film. The results demonstrated that exchange bias higher than coercivity (\mu0Hex\gg \mu0Hc) was realized near room temperature. [ABSTRACT FROM PUBLISHER]

Abstract: To confirm the origin of the exchange coupling through the nano-oxide layer (NOL), the detailed analyses of the magnetization curve and the temperature dependence on magnetization for the Co1-xFex-NOL samples with various oxidation processes are investigated. The field cooling effect is observed for NOL-inserted samples, which suggests the existence of the antiferromagnetic (AFM) component in the NOL. The characteristic temperature (blocking temperature) increases with increase in the Fe content for Co1-xFex(x=0.08,0.17,0.26)-NOL. These results support that NOL pinning appears higher than room temperature. Further, the twisted coupling through the NOL observed for the Co0.50Fe0.50-NOL is discussed from the viewpoint of the magnetic roughness due to the ferrimagnetic nature of the very thin NOL in specular spin valve (SPSV). [Copyright &y& Elsevier]

Presents a study that examined the use of current perpendicular to plane giant magnetoresistive (CPP-GMR) heads for magnetic recording. Requirement for CPP-GMR film; Features of developed CPP-GMR films with high performance; Analysis of the head structure optimization for CPP-GMR.

We investigated the effect of Pt insertion on a Cr2O3/Co exchange coupling system. The perpendicular exchange bias μ0Hex decreased with increasing Pt insertion layer thickness, and we observed positive μ0Hex for samples with relatively thick Pt insertion layers. We also examined the cooling field μ0Hfc dependence of μ0Hex for the samples. At small μ0Hfc, all samples exhibited negative μ0Hex. With increasing μ0Hfc, a shift of μ0Hex from negative to positive was observed. In the past, similar behaviors were observed for FeF2/Fe systems exhibiting positive μ0Hex. In addition, the μ0Hfc dependence of μ0Hex was well fitted by an equation taking into account the Zeeman energy at the surface of an antiferromagnet as well as an antiferromagnetic exchange coupling. The results strongly suggest that (1) Cr2O3 surface spin is affected by the external magnetic field and (2) the coupling at the Cr2O3/Pt/Co interface is antiferromagnetic. [ABSTRACT FROM AUTHOR]

We investigate the magnetic, electric, and magnetoelectric properties of a Cr2O3 thin film system that was deposited by radiofrequency magnetron sputtering. The temperature dependence of the magnetic susceptibility of our Cr2O3 film is similar to that of bulk Cr2O3, which indicates a small oxygen non-stoichiometry in the film. The Cr2O3 film exhibits high AC resistivity (∼109 Ωcm) and low leakage current (4.0×10-5 A/cm2 at E=80 kV/cm). Finally, we demonstrate magnetoelectric switching of the exchange bias using the Cr2O3/Pt/Co all-thin-film system. By changing the direction of the electric field during the magnetoelectric field cooling process, the exchange bias field was changed symmetrically from -160 Oe to +160 Oe, which represents the switching of the antiferromagnetic domain of Cr2O3. [ABSTRACT FROM AUTHOR]

In this study, we fabricated a Cr2O3 (0001) film without and with a Pt buffer layer and investigated its effect on perpendicular exchange coupling in a Cr2O3/Co3Pt interface. The results showed that the exchange bias field (μ0Hex) and blocking temperature (TB) of a Cr2O3 film without and with Pt were very different. The Cr2O3 film without Pt had a lower μ0Hex of 176 Oe and a lower TB of 75 K, whereas that with Pt had a higher μ0Hex of 436 Oe and a higher TB of 150 K. We discussed this difference in μ0Hex and TB values based on collinear/non-collinear coupling in a ferromagnetic and antiferromagnetic interface using Meiklejohn and Bean's exchange anisotropy model. [ABSTRACT FROM AUTHOR]

Deposition of ZnO thin films on a ferromagnetic metallic buffer layer (Co3Pt) by molecular beam epitaxy technique was investigated for realization of ZnO-based magnetic tunneling junctions with good quality hexagonal ZnO films as tunnel barriers. For substrate temperature of 600 °C, ZnO films exhibited low oxygen defects and high electrical resistivity of 130 Ω cm. This value exceeded that of hexagonal ZnO films grown by sputtering technique, which are used as tunnel barriers in ZnO-MTJs. Also, the effect of oxygen flow during deposition on epitaxial growth conditions and Co3Pt surface oxidation was discussed. [ABSTRACT FROM AUTHOR]

The spin valve films with the insertion of a nano-oxide-layer are expected as nano-constriction SV MR devices such as nano-contact MR. However, the nature of those magnetic coupling, such as the exchange bias and interlayer coupling in SV films with the insertion of a NOL have been not well discussed. In this paper, the interlayer coupling field through Cu spacer and its temperature dependency in SVs with Co1-xFex-NOL and Co1-xFex/Cr-NOL are studied to confirm the influence of the insertion of NOL into SV films. In the case of the SVs with Co0.9Fe0.1-NOL and Co0.9Fe0.1/Cr-NOL, negative interlayercoupling field increases with decreasing temperature in spite of the strength of the Néel coupling of those are almost same with the full metal SV at room temperature. It suggests that the antiferromagnetic interlayer coupling appears by the insertion of NOL into the SVs even though the rough interface. From the result of the temperature dependencies of Hin for each sample, it is considered that the phase of the antiferromagnetic interlayer coupling which related the intensity is varied by the insertion of NOL into the SVs. [ABSTRACT FROM AUTHOR]

When the surface energy of bottom layer is lower than top layer, the atoms of bottom layer should be pumped up at the triple point of the grain boundary. This phenomenon should be useful for the fabrication of well-defined nanobridge. To confirm the Atom Pumping-Up mechanism for metal/metal thin films, Ta(2 nm) on epitaxial MgO(001)IFe(001) films were prepared by the electron beam deposition method. The Pumping-Up mechanism was successfully confirmed by the Auger Electron Spectroscopy, the in situ Scanning Tunneling Microscopy, and the Transmission Electron Microscope observation after heat treatment of 400 ° C × 30 min. The size of the Fe bridges was 2-5 nm. Furthermore, the magnetic exchange coupling effect on the magnetization process through the ferromagnetic bridges between two Fe layers in MgO/Fe/Ta/Fe after Atom Pumping-Up shows a good agreement to the micromagnetics simulation result from the assumption of ferromagnetic bridges with the size of 1-4 nm. [ABSTRACT FROM AUTHOR]

To understand the mechanism of current-confined-path formation for the current-perpendicular-to-plane type of giant magnetoresistive devices, we have investigated the evolution of an Al monolayer on the Cu (111) surface both by in situ scanning tunneling microscopy and by molecular dynamics simulation. Ultrathin Al nano-clusters were formed on the plateaus and step (or plateau) edges of the Cu surface in the as-deposited state. Upon annealing at 300 °C, Al atoms migrated toward the step edges by surface diffusion. As a consequence, nanometer-sized Cu channels not covered by Al clusters can be formed. These channels could serve as current-confined paths if subsequent mild Al oxidation is provided. [ABSTRACT FROM AUTHOR]

The bulk and interface spin scattering asymmetric coefficients, βF and γF/N, respectively, as well as the interfacial specific resistance, AR*F/N, contribute to the total resistance change-area product, ΔRA, in current-perpendicular-to-plane (CPP) geometry. In this paper, we report the effect of the insertion of a 1 nm Fe layer into ferromagnetic (F)/non-ferromagnetic (N) interfaces on the spin dependent transport properties. Using the Valet-Fert theory based on the two-current model in which ΔRA is obtained as a function of thicknesses of the ferromagnetic layer (3, 4, and 5 nm), we experimentally deduced the values of βF, γF/N, and AR*F/N of exchange-biased spin valves (EBSVs) for an artificially ordered B2 state Fe50Co50 alloy as a magnetic layer and an Ag spacer layer. [ABSTRACT FROM AUTHOR]

Using current-perpendicular-to-plane (CPP) giant magnetoresistance (GMR) measurement, we have evaluated the bulk and interface spin scattering asymmetric coefficients, βF and γF/N and the specific interfacial resistance, AR*F/N, for exchange-biased spin-valves consisting of artificially ordered B2 structure Fe50Co50 and Ag spacer layer. Artificially epitaxial ordered Fe50Co50 superlattices have been successfully fabricated on MgO (001) substrate by alternate monatomic layer (AML) deposition at a substrate temperature of 75 °C. The structural properties of the full epitaxial trilayer, AML[Fe/Co]n/Ag/AML[Fe/Co]n, on the Ag electrode have been confirmed by in situ reflection high-energy electron diffraction and transmission electron diffraction microscopy. A considerably large resistance-area product change and MR ratio (ΔRA > 3 mΩμm2 and MR ratio ∼5%) were confirmed even at thin AML[Fe/Co]n layer at room temperature (RT) in our spin-valve elements. The estimated values of βF and γF/N were 0.80 and 0.84 ± 0.02, respectively, from the Valet-Fert theory analysis of ΔRA as a function of thickness of the ferromagnetic layer (3, 4, and 5 nm) on the basis of the two-current model. [ABSTRACT FROM AUTHOR]

Presents a quantitative study of the ferromagnetic interlayer coupling of the Nano-Oxide Layers. Magnetoresistive ration of spin-valves; Details on the experiment; Results and conclusion.

Presents a study on annealing time and temperature dependences of magnetoresistive (MR) ratio in CoFe/Cu spin-valves. Experimental procedures; Results; Conclusion.

The linear magnetoelectric effect was measured in 500-nm Cr2O3 films grown by radio frequency sputtering on Al2O3 substrates between top and bottom thin film Pt electrodes. Magnetoelectric susceptibility was measured directly by applying an alternating current (ac) electric field and measuring the induced ac magnetic moment using superconducting quantum interference device magnetometry. A linear dependence of the induced ac magnetic moment on the ac electric field amplitude was found. The temperature dependence of the magnetoelectric susceptibility agreed qualitatively and quantitatively with prior measurements of bulk single crystals, but the characteristic temperatures of the film were lower than those of single crystals. It was also possible to reverse the sign of the magnetoelectric susceptibility by reversing the sign of the magnetic field applied during cooling through the Néel temperature. A competition between total magnetoelectric and Zeeman energies is proposed to explain the difference between film and bulk Cr2O3 regarding the cooling field dependence of the magnetoelectric effect. [ABSTRACT FROM AUTHOR]

Abstract: The Ni nano constriction dots embedded in the Ta-nano-oxide layer (NOL) was prepared by the ion beam sputtering (IBS) method. After the various conditions of the oxidations, the structural analyses of the NOL were performed by RHEED, AES and in situ STM/AFM observations. From the current image of the conductive AFM for NOL, the periodically aligned metallic dots with the size around 5–10nm were successfully observed. The mechanism of the formation of the self-organized aligned Ni nano constriction dots is discussed from the standpoint of the grain size, the crystal orientation, the preferred oxidation of Ta at the diffused interface. [Copyright &y& Elsevier]