Synthetic spin valves with structure of sub/Ta/NiFe/IrMn/AP2/Ru/AP1/Cu/CoFe/Ta were systematically studied by varying the Ru thickness in the artificial antiferromagnetic structure. Spin-valve films were deposited using a Nordiko 9606 PVD system and annealed in a magnetic field of 6 kOe parallel to the easy axis of the free layer. MR(H) and M(H) curves of these spin valves were experimentally measured and quantitatively simulated using Boltzmann transport equation and coherent magnetization rotation model. The corresponding interlayer exchange coupling and pinning angle of these spin valves were determined from simulation. Both experimental measurement and simulation results have shown that the characteristics of synthetic spin valves depend strongly on the thickness of Ru. The pinning field for spin valves with ultrathin Ru layer was canted. This was evidenced in the reduction of the measured MR ratio and shape of MR curve when Ru is thinner than 0.5 nm. It is concluded that the pinning angle is determined by the spin–flop angle of one of the pinned layers (AP2) at spin–valve annealing temperature, which is in turn determined by the final balance between the interlayer antiferromagnetic coupling field and the external applied magnetic field during annealing.

A new spin-filter spin valve with nano-oxide specular layers with structure of Ta/NiFe/IrMn/CoFe/NOL1/CoFe/Cu/CoFetfl/CutCu/NOL2/Ta was deposited using a Nordiko 9606 physical vapor deposition system. The data clearly show that the magnetoresistive (MR) ratio has been significantly improved for spin valves with thinner free layers. The MR ratio remains larger than 12% even when the CoFe free layer is as thin as 1 nm. An optimized MR ratio of ∼15% was obtained when tfl was about 1.2 nm and tCu about 1.5 nm, and was a result of the balance between the increase in the electron mean free path difference and current shunting through the conducting layer. It is also found that the Cu enhancing layer can improve soft magnetic properties of the CoFe free layer due to the low atomic intermixing observed between Co and Cu. The CoFe free layer of 1–4 nm exhibited coercivity of ∼3 Oe after annealing in a static magnetic field. This kind of spin valve with a very thin soft CoFe free layer is particularly attractive for ultra high density read head applications.

An antiferromagnetic materials AFM such as NiMn, PtMn, IrMn, FeMn, NiO etc.have been used as an exchange layer in spin-valve devices 'GMR/TMR'to provide pinning field between the exchange layer and pinned layer. In this paper we studied the effect of IrMn roughness on the exchange coupling with CoFe in simple bottom spin-valve structure, Ta/IrMn/CoFe/Cu/CoFe/Ta.Nordiko 9606PVD system was used to fabricate the spin valve structure. The system integrated with load lock to sustain the vacuum integrity at base pressure of 2 x 10.'Torr and it is populated with six targets.The IrMn roughness can be varied by changing the process pressure during the IrMn deposition. The roughness was measured using atomic force microscope. A VSM with MR probe also used to measure the MR ratio and exchange coupling. Film resistivity and composition analysed using four probe technique and XRF respectively.In this paper we also studies the effect of the roughness on spin-valve with dual nano oxide layer NOL structure Ta/IrMnThe shared pole in a merged recording head design serves as the reader shield and a part of the writer circuit. A good shared pole design should provide permeable path to the write flux, efficiently shield the reader from adjacent recorded transitions and prevent magnetic coupling between the reader and writer. This paper will report the feasibility of using A1203 as the nonmagnetic and non-conducting spacer in a trilayer shared pole structure of type -NiFe /Ab03 (x) /NiFe, with x = 0.1-1.0 pm. The shared pole structure was integrated into head design and its effect on head stability and performance was studied.In-line electrical probe was used to measure electrical isolation across the Alumina spacer layer. Voltage breakdown measurements were carried out under varying voltage bias conditions (2V, 20V, 40V and lOOV) for devices with x = 0.1 to 1 .O pm. Structures with with Alumina layer thickness = 1.0 pm showed 100% yield at all bias conditions. At applied voltage values <: 20V, isolation probe yield (as shown in fig. 1 ) increases withAlumina thickness values. Kerr imaging was used to study the magnetic domains in the shared pole structure (Fig.2). Domain configuration of the trilayer structure studied here can be described by the Slonczewski model for magnetic laminates [l]. Detailed results will be discussed in the paper. Fig.1. Isolation probe yield data for Fig. 2 Kerr image of trilayer shared different Alumina spacer thickness. pole with 0.2um M,O, spacerElectrical testing was carried out on heads with various shared pole designs to study reader stability and writer-reader interactions. Performance was found to vary as a function of Alumina spacer thickness. It was interesting to note that parts with thinnest Alumina spacer (0.lum) showed relatively higher reader instability related to write events (magnetic coupling between writer and reader) and stray fields from domain walls in the shields.[I] Slonczewski et al, IEEE Trans Mag. 24, p.2045, 1988 BP 04 BP 05

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