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University of Nebraska - Lincoln

Si-Hwang Liou Publications

1997

Articles 1 - 4 of 4

Full-Text Articles in Physics

High Temperature Superconducting Josephson Junctions In A Stacked Bicrystal Geometry, H.Q. Li, R.H. Ono, L.R. Vale, D.A. Rudman, Sy_Hwang Liou Aug 1997

High Temperature Superconducting Josephson Junctions In A Stacked Bicrystal Geometry, H.Q. Li, R.H. Ono, L.R. Vale, D.A. Rudman, Sy_Hwang Liou

Si-Hwang Liou Publications

Bicrystal grain boundary Josephson junctions were fabricated in a stack of two layers of YBa2Cu3Oχ separated by epitaxial SrTiO3. Weak link behavior was observed in the bridges formed in both layers that had similar shunted-junction characteristics but significantly different critical currents. Characteristic voltages up to 1.9 mV were measured at 4.5 K. The resonant structure was seen in the current–voltage characteristics of the upper-layer junctions, and interactions between junctions in the two layers were evident.


An Improved Multi-Layer Fabrication Process For Yba2Cu3O7-X-Based Circuits, H.Q. Li, R.H. Ono, L.R. Vale, D.A. Rudman, Sy_Hwang Liou, W.H. Mallison Jun 1997

An Improved Multi-Layer Fabrication Process For Yba2Cu3O7-X-Based Circuits, H.Q. Li, R.H. Ono, L.R. Vale, D.A. Rudman, Sy_Hwang Liou, W.H. Mallison

Si-Hwang Liou Publications

Improved via connections in structures of YBa2Cu3O7-x/SrTiO3/ YBa2Cu3O7-x (YBCO/STO/YBCO) multilayers have been made using a combined HF wet-etching and ion-milling process. The critical current density Jc of the via is as high as 2×106 A/cm2 at 76 K, and is dominated by edge contacts in the ab-plane, YBCO and Sr2AlNbO6 (SAN) multilayer test circuits were also made with this process. The 4° crossovers in a SAN test chip had a critical temperature Tc of 88 K ...


Enhanced Temperature Effect On Magnetoresistance In Fe/Mo Multilayers, M.L. Yan, Y.W. Lai, L. Yin, Sy_Hwang Liou Apr 1997

Enhanced Temperature Effect On Magnetoresistance In Fe/Mo Multilayers, M.L. Yan, Y.W. Lai, L. Yin, Sy_Hwang Liou

Si-Hwang Liou Publications

We have observed an enhancement of the temperature effect on magnetoresistance (MR) in Fe/Mo multilayers with the increase of the Mo layer thickness. MR at the first antiferromagnetic maximum is large and insensitive to the temperature whereas at the third antiferromagnetic maximum it is small and relatively sensitive to the temperature. We found that the mean free path of the conduction electrons increased with the increase of the Mo layer thickness at a fixed temperature and it decreased very slightly with the increase of the temperature at a fixed Mo layer thickness. The interlayer coupling, similar to MR, also ...


High Resolution Imaging Of Thin-Film Recording Heads By Superparamagnetic Magnetic Force Microscopy Tips, Sy_Hwang Liou, S.S. Malhotra, John Moreland, P.F. Hopkins Jan 1997

High Resolution Imaging Of Thin-Film Recording Heads By Superparamagnetic Magnetic Force Microscopy Tips, Sy_Hwang Liou, S.S. Malhotra, John Moreland, P.F. Hopkins

Si-Hwang Liou Publications

We have used superparamagnetic magnetic force microscopy (MFM) tips to obtain high spatial resolution MFM images of recording heads. Profiles of the magnetic field gradient above a thin-film recording head under 3 mA bias current to the head and various tip-head distance conditions are presented. At a low tip-head distance, the gap width, gap location, and gap-field structure can be well resolved in these MFM images. Superparamagnetic tips show promise for the magnetic imaging of recording heads with gap widths below 200 nm.