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The properties of interfaces between normal (N) and ferromagnetic (F) metals are described by enhanced specific resistance and scattering asymmetry. The specific resistance and scattering asymmetry of sputtered standard Py/Cu, Co/Cu and Fe/Cr interfaces are studied.

The current-driven switching in nanofabricated magnetic F1/N/F2 trilayers (nanopillars) is examined. A square switching diagram at 4.2 K and rounded at 295 K is observed in magnetic trilayer nanopillars.

Current perpendicular magnetoresistance measurements are presented for a series of Ni66Fe13Co21 permalloys are presented.

We have measured Giant Magnetoresistance (GMR) with Current Perpendicular to the layer Planes (CPP-MR) in Exchange-Biased (EB) spin-valves - a controllable spin-switch. We will present CPP data on EB-spin-valves of Permalloy (Py) and Cu, and explain how the data are analyzed. Interpreted with the theory of Valet and Fert, the data yield an unexpectedly short value for the length over which electrons lose spin-memory in Py, the spin-diffusion length, [Mathematical Expression Omitted]. We will show that the CPP parameters derived with the aid of single EB-spin-valves predict rather well the CPP-MRs of double EB-spin-valves.

The current flow perpendicular to the layer plane magnetoresistance (MR) of magnetic multilayers enables the isolation of finite spin diffusion length effects. These effects are exhibited in multilayers which have alloys such as Ag and Cu with Mn as an impurity. The data obtained from the investigation of AgMn indicate the presence of negative linear MR lines.

A two-channel electronic conduction model was used to characterize the magnetorsistance of Ag/Co and AgSn/Co multilayered thin film structures with currents flowing perpendicular to the layer planes. The predictions of the model were compared with those of a series resistor formulation. Spin dependent parameters for both Ag/Co and AgSn/Co multilayers wre presented.

From measurements of the Current-Perpendicular-to-Plane (CPP) resistances and magnetoresistances (MRs) of sputtered [[F/Al].sub.N] (F= Co, Fe, [Co.sub.91][Fe.sub.9]) multilayers with N-bilayers, and F/Al-based exchange-biased spin-valves, we estimate interface specific resistances, 2A[R*.sub.F/Al], and scattering asymmetries, [[gamma].sub.F/Al], for each metal pair at 4.2 K. In all three cases, 2A[R*.sub.F/A1] is large and [[gamma].sub.F/Al] is small, comparable to the recently determined values of 2A[R*.sub.Py/Al] ~ 9 f[OMEGA][m.sup.2] and [[gamma].sub.Py/Al] ~ 0.03 for Permalloy (Py)/Al interfaces. The values of 2A[R*.sub.F/Al] with Al are too large to be explained by the resistivities of alloyed F/Al interfaces. The similarity of results for Py, Fe, Co, and [Co.sub.91] [Fe.sub.9] suggests that spin dependent scattering at F/Al interfaces is determined mainly by the properties of Al. We find that F/Al interfaces are not stable over time at 295 K or upon annealing to 450 K. Index Terms--Current perpendicular-to-plane (CPP) magnetoresistance (MR), interface resistance, interface scattering asymmetry.

The resistivity of sputtered Ru, the spin-diffusion length in Ru layers, the interface specific resistances of Cu/Ru and Co/Ru interfaces and the spin-scattering anisotropy at Co/Ru interfaces are examined. Due to the two additional Co/Ru interfaces, the total AR increased by ~1 f omega m(super 2).

A study was conducted to analyze a novel technique of measuring the loss of spin-direction memory in nonmagnetic materials and at nonmagnetic interfaces. The method involves inserting the material of interest into an exchange-biased spin-valve. In addition, the associated reduction in the spin valve is observed in the magnetoresistance determined with the current perpendicular to the plane.

A study was conducted to determine a value of beta for a Ni97Cr3 alloy using spin valves based upon permalloy. The hybrid spin valves were deposited onto silicon substrates using mutitarget sputtering without breaking vacuum. Each spin valve was sandwiched between crossed niobium stripes to realize uniform current flow. Experimental results indicated an estimate that provides additional support for an approximate universality of values of beta.

We present the first measurements of the specific resistance change, AAR, with increasing Co layer thickness, [t.sub.Co], of current-perpendicular (CPP) exchange-biased spin-valves (EBSVs) of Co and Cu. A[Delta]R grows about as predicted for a long spin-diffusion length in Co until about [t.sub.Co] = 20 nm, after which it grows more slowly than predicted. Possible reasons for this deviation from prediction are considered, including a short spin-diffusion length in Co. Index Terms: Giant Magnetoresistance; Magnetic Multilayers; Spin-valve.

Experimental analysis of the magnetic states of as-sputtered magnetic multilayers reveals that the magnetic states Ho and Hp of the Ag/Co and Cu/Co multilayers are well-defined. The magnetic properties of the multilayers change in a systematic manner with respect to other multilayer parameters. The Hp state of the multilayers does not denote the statistically uncorrelated state.

An Ag/Al interface specific resistance is measured that is twice than predicted for a perfect interface and even larger than the newly predicted 1.3 f[omega] [m.sup.2] for a 4 ML 50%-50% alloy. The predicted anisotropy ratio of more than 4 for a perfect interface is reduced to less than 2 for a ML interface, which has made it harder to detect any such anisotropy.

The low frequency, current-driven magnetization dynamics in partially patterned Py/Cu/Py, elliptical, nanopillars, with the top Py magnetic layer and part of the Cu layer shaped into a nanopillar and the rest left extended is observed. The behaviors of spin-transfer-torque curves for applied magnetic field H and several behaviors similar to those associated with excitation and dynamics of vortices are described.

Two simple tests are described for models of current-induced magnetization switching due to spin-transfer torque in ferromagnetic/nonmagnetic/ferromagnetic (F/N/F) trilayers. The experimental ratio of [I.sup.+]/[I.sup.-] is compared for Cu and CuGe with the three models that make predictions.

Systematic measurements of resistance dependence on the angle between the magnetizations in magnetic multilayers at 4.2 K, with varied configurations and thickness of one of the layers are reported. It is shown that the data for trilayers with the smallest thickness of one of the ferromagnetic layers are inconsistent with the existing models.

Magnetoresistance (MR) and switching current at room temperatures are compared along with 4.2 K for Permalloy/N/Permalloy nanopillars undergoing current-induced magnetization switching (CIMS), with nonmagnetic metals N=Cu, Ag, and Au. Results suggest that Ag and Au represent potentially viable alternatives for CIMS studies and devices to the more widely used Cu.

Findings on how current-driven magnetization switching and magnetoresistance in nanofabricated magnetic multilayers are affected are presented. The findings are affected by varying the spin-scattering properties of the nonmagnetic spacer, the relative orientations of the magnetic layers, and the spin-dependent scattering properties of the interfaces and the bulk of the magnetic layers.

Majority electrons scatter strongly in dilute Fe(Cr) alloys and at Fe(Cr)/Cr interfaces. Normal magnetoresistance and an inverted current-driven switching display by Fe(Cr)/Cr/Fe(Cr) trilayer nanopillars is shown.

The measurements of a spin-diffusion length at 4.2 K in sputtered Au, spin-memory-loss at Au/Cu interfaces and Au/Cu interface specific resistance are presented. It is also shown that the exchange biased spin valves with Au sandwiched between Co layers produce changes in specific resistance, A DELTA R, comparable to those for Cu and Ag.

Magnetic properties of soft films are usually affected by extrinsic properties such as easy axis dispersion and domain structure, which are dependent on deposition conditions, microstructures, alloy compositions, and internal stresses. The best potential for application in high frequency magnetic devices, in particular, recording write heads, due to the high saturation magnetization and well-defined uniaxial anisotropy is shown.

An optical-lithography-based sample preparation technique for measuring the current-perpendicular-to-plane (CPP) magnetoresistance with micron-size current-contact areas on top of magnetic multilayer samples of millimeter in-plane size is described. Still employing superconducting contacts, can produce resistance from a single contact area of current flow that is large enough to be measured by nanovoltmeter-based techniques