By the two-dimensional triangular holey structure, a high-power stable single-mode operation was demonstrated in oxide confined 850nm vertical-cavity surface-emitting lasers. For two types of hole alignments, the lasing operation was observed with different near field patterns, i.e., a single spot pattern and a floral pattern. The former showed an output power of 2mW with a high side-mode suppression ratio (SMSR) of 45–50dB, which is explained by the selective loss mechanism. The latter showed a high power of 7mW with a SMSR of 40dB. The observed lasing spectrum and far field pattern indicate that it is a deformed fundamental mode whose bright spots extending over the device are in-phase oscillating. This device structure will be effective for the enhancement of single-mode power in devices with any material system.

Shielded current perpendicular to the plane (CPP) spin valve heads with about 20 Gbit/in.2 dimensions were fabricated and tested both quasistatically and dynamically. Dual synthetic spin valves with 2.3 mΩ μm2 of resistivity change and area product (dRA) was used. Quasistatic tests were conducted to determine the current efficiency loss caused by the specific CPP head structure. Dynamic tests were performed to examine the flux efficiency of the readback process in the spin valve element, in order to confirm the calculation results which take into account the increase of effective anisotropy field caused by the circular sense current field. Output voltage of about 260 μV (peak to peak) was successfully obtained from the dynamic tests. Finite element modeling analysis of current distribution and temperature rise, together with degradation experiments with excessive sense current, was conducted to predict the maximum allowable current density in the 200 Gbit/in.2 dimension, where read track width and stripe height are assumed to be 100 nm. With these results, requirements of spin valve material properties (dRA, RA) and the CPP structure was predicted. Essential issues to satisfy the requirements and possible solutions are also discussed.

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The head efficiency of shielded current perpendicular to the plane (CPP) spin valve heads of 20 and 200 Gbpsi dimension has been computed and analyzed by an analytical approach utilizing the transmission line model (TLM), and a numerical approach using micro magnetic simulation. For the TLM, the effect of the circular current field was taken into account by incorporating the distribution of the effective permeability of the free layer. Both results showed higher head efficiency for the configuration where sense current field cancels the hard bias field at the front side (air-bearing side) of the free layer. The difference of efficiency by sense current direction was significant at higher sensor height and stronger hard bias. The effect was also observed experimentally on transfer curves from CPP spin valve heads of 20 Gbpsi dimension.