We describe a versatile portable prototype device for electrical measurements of ''soft'' materials. It consists of a custommade micromanipulator and a gas-tight syringe to hold a mercury mini-drop to make reliable and controllable electrical contacts with solid-state materials of interest. Compared with the conventional method (deposition of thin metal films under vacuum), the proposed experimental approach is simpler and more cost-effective.

The use of selective-area metal-organic vapor phase epitaxy, which is our bottom-up formation approach, to fabricate MnAs nanocluster composite arrays in which two nanoclusters are formed in close proximity at an angle of 1208 and with a spatial gap of around 20 nm on GaAs (111)B substrates is reported in this paper. The magnetic reversals of the nanoclusters in the composite arrays are observed depending on the strengths and directions of the applied external magnetic fields at room temperature. The applied external magnetic fields for the magnetic reversals in one of the nanoclusters in the composites are possibly from 750 to 1000 Gauss (G). The characterization results obtained using magnetic force microscopy show that the magnetic reversals in the nanoclusters are independently controlled in nanocluster composites. Finally, we discuss the designing of the nanocluster size, shape, and arrangement to control the magnetization directions in the nanoclusters in the composites for possible application to magnetic logic operations based on the results of the magnetic reversals in the nanoclusters.

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Selective‐area metal‐organic vapor phase epitaxy is used by Hara and Komagata (pp. http://doi.wiley.com/10.1002/pssb.201552083) as a bottom‐up formation approach (see schematic illustration of sample preparation on the cover) to fabricate ferromagnetic MnAs nanocluster (NC) composite arrays in which two NCs are formed in close proximity at an angle of 120° and with a spatial gap of around 20 nm on GaAs (111)B substrates (cf. the scanning electron microscope, SEM, and atomic force microscope, AFM, images bottom left). Magnetic reversal of the NCs in the composite arrays is observed depending on the strengths and directions of the applied external magnetic fields, B, at room temperature. Magnetic force microscopy (MFM) characterization results show that the magnetic reversals are independently controlled in one of the two NCs in the composites, i.e., in the free NCs (on the right: MFM images showing the dependence of magnetic reversals on the B direction). The authors use these results to propose possible application to magnetic logic operations by designing the NC size, shape, and arrangement to control the magnetization directions in the NCs in the composites.