摘要:

The dielectric-base transistor (DBT) is expected to be coupled with various functional oxides such as high-temperature superconductors and ferroelectrics. We experimented with lowering the conduction band of the channel to reduce the operating voltage.LaTiO3deposited onSrTiO3supplies carriers in theSrTiO3substrate by displacingSr2+andLa3+.With this technique, we fabricated aYBa2Cu3O7−x/In2O3/SrTiO3/LaTiO3/SrTiO3transistor with a partially doped channel. The transistor operates at under 1 V while maintaining a voltage amplification factor of 2, which is one order smaller than the 15 V operating voltage of a transistor with an undoped channel. The base potential relative to the emitter conduction band has been reduced to 0.3 eV. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119047

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The microstructure ofYBa2Cu3O7−&dgr;(YBCO) grain boundaries obtained at step edges on (001)LaAlO3substrates have been studied by scanning and transmission electron microscopy. A typical morphology of the YBCO grain boundaries is distinguished by two parts where the parts are expected to have different junction properties. One part of the boundary is caused by the difference in nucleation probability between the (001) surface and the inclined step facet. The second morphology is developing as a result of minimization of the YBCO surface energy. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119048

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The magnetic exchange anisotropy of a series of single crystalCo1−xMnx/Mnbilayers (0⩽x⩽ 0.37) is studied as a function of the Mn content. By means of ferromagnetic resonance, it is found that the exchange anisotropy shows up when 0.30⩽x⩽0.37 and disappears whenx⩽0.20at room temperature. The phenomenon of Mn enrichment is observed at the Co–Mn surface by the technique of varying angle x-ray photoelectron spectroscopy, which may lead to the formation of antiferromagnetic Mn-rich interface regions and, hence, results in the exchange interaction between the ferromagneticCo1−xMnxfilm and the antiferromagnetic Mn-rich interface region. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119049

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have synthesizedLa0.83Na0.11MnO2.93by heatingLa2O3andMnCO3in NaCl melt at 900 °C. The exact composition was arrived by analyzing each ion by an independent chemical method. The compound crystallized in a rhombohedral structure and showed an insulator-to-metal transition at 290 K. Epitaxial thin films were fabricated onLaAlO3(100) using a pulsed laser deposition technique. The film also showed an insulator-to-metal transition at 290 K. Magnetoresistance[&Dgr;R/R0=(RH−R0)/R0]was−71&percent;near the insulator-to-metal transition temperature of 290 K at 6 T magnetic field. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119050

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Static magnetic and spin wave properties of square lattices of permalloy micron dots with thicknesses of 500 and 1000 Å and with varying dot separations have been investigated. A magnetic fourfold anisotropy was found for the lattice with dot diameters of 1 &mgr;m and a dot separation of 0.1 &mgr;m. The anisotropy is attributed to an anisotropic dipole–dipole interaction between magnetically unsaturated parts of the dots. The anisotropy strength (order of105 erg/cm3) decreases with increasing in-plane applied magnetic field. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119051

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Exchange induced unidirectional anisotropy has been observed in a new bilayer system consisting of a ferromagnetic FeTaN orNi80Fe20film coupled to an antiferromagnetic Cr–Al alloy film. Estimates of the exchange coupling energy and magnetic anisotropy constant of the antiferromagnet are made and compared to other exchange coupled systems. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119052

出版商:AIP    

年代:1997

数据来源: AIP