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In this work, the tungsten‐copper composites were fabricated by binder jet 3D printing technology. The effects of different printing layer thicknesses (50 μm to 100 μm) on the green density and green strength were investigated. Then, under the optimal layer thickness, the effects of different sintering temperatures (1300 °C to 1600 °C) on the microstructure and densification of tungsten‐40 wt.–% copper composites were studied. The experimental results showed that when the printing layer thickness was set as a lower value (50 μm), the tungsten‐40 wt.–% copper green part had the best strength and its density reached a maximum value of 60.73 %. After sintering for green parts printed with 50 μm layer thickness, the relative density, thermal conductivity and electrical conductivity of sintered parts first increased and then decreased with increasing sintering temperature. In our experiments, the tungsten‐40 wt.–% copper sample fabricated by binder jet 3D printing with a printing layer thickness of 50 μm under a sintering temperature of 1500 °C displayed the best properties, in which the relative density, thermal conductivity and electrical conductivity were 97.04 %, 228 W⋅m−1⋅K−1 and 46.5 % IACS, respectively. [ABSTRACT FROM AUTHOR]

The preparation of a family of wide-band-gap ternary oxide ferromagnetic semiconductor films with high transition metal concentration is presented. The wide gap oxide ferromagnetic semiconductors with controllable spin-polarized electrical transport could find significant application in spintronics devices as a spin injection source.

[Ge.sub.1-x][Mn.sub.x]/Ge single-crystal heterojunction diodes with p-type [Ge.sub.1-x][Mn.sub.x] ferromagnetic semiconductor are grown on Ge substrates of p-type, n-type and intrinsic semiconductors by using molecular beam epitaxy. The I-V curve of the p-[Ge.sub.0.95][Mn.sub.0.05]/intrinsic-Ge diode is tuned by a magnetic field, which is shown by a large positive magnetoresistance.