The multilayer thin films having the form of Ti(30 nm)/Fe(dFe)/[Nd–Fe–B(dNd–Fe–B)/Fe(dFe)] ×5/Ti(30 nm)/glass were fabricated on glass substrates by means of radio frequency (rf) sputtering, with dFe varied from 0 to 50 nm and dNd–Fe–B from 0 to 100 nm. Magnetization measurements have revealed that the minor loops of the films are reversible in a certain range of demagnetization fields except for the films with dFe∼0 nm or dNd–Fe–B<10 nm. Micromagnetic calculation of magnetization curves has been performed, which has well reproduced the observed hysteresis loops including spring-back behavior and the dependence of the coercive field HcJ on dFe and dNd–Fe–B. From the comparison between experiment and calculation, we can infer that the interlayer exchange-coupling strength is about 10% of the intralayer couplings, which are found to be almost independent of dFe and dNd–Fe–B.

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We have investigated the performance of dual spin valve heads in the current-perpendicular-to-plane (CPP) geometry on dynamic electrical tests (DET) and quasi-static tests (QST). Shielded CPP reader and stitched pole writer composite heads were fabricated. A various physical read track width and area of the dual spin valve element were deliberately obtained in the range of 41-175 nm and 0.0034-0.022 m 2 , respectively. Materials used for the CPP dual spin valve are Co 90 Fe 10 , Ni 80 Fe 20 , Cu, Ru, Ta, and Pt 50 Mn 50 , which are common in industrial current-in-plane (CIP) spin valves. The shape and smoothness of QST transfer curve, readback waveform, micro-track, and full-track profiles of the narrow read track CPP heads are essentially just the same as those of CIP spin valve. A track-average-amplitude of 0.6 mV was obtained at the bias current density of element around 100 MA/cm 2 in the CPP head with the physical read track width of 47 nm. Overall reader resistance of the CPP heads at head gimbals assembly (HGA) level was in the range of 10-35 and proved to be well appropriate.Index Terms-Current-perpendicular-to-plane (CPP) geometry, giant magnetoresistance, narrow track, spin valve head.

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Thin-film nanocomposite magnets, composed of α-Fe and c-axis oriented SmFe12 phases, have been synthesized by rf magnetron sputtering onto heated glass substrates. For samples with the α-Fe volume fraction VFe<30%, the demagnetization curves with fields applied normal to the film plane exhibited good squareness, while the hard-axis curves did not saturate even in a field of 140 kOe at room temperature. Both the coercivity and maximum energy product showed a maximum for VFe≈25%.