Resistivity of MnB₄

In an effort to develop super hard materials, MnB₄ was recently synthesized for the first time in single crystalline form, with micro scale crystals of about 200 μm length. Subsequently, the magnetic properties have been studied experimentally, and band structure calculations have been carried out. Based on these calculations and preliminary resistivity measurements, it was argued that the material is semiconducting, although a definite conclusion could not be reached. In order to determine whether MnB₄ is a semiconductor or a metal we have carried single crystal resistivity measurements at temperatures 2 to 300 K. For this purpose a setup for measuring micro-scale samples was developed and characterized. The setup is based on a modified two point configuration and the resistivity of MnB₄ was measured as function of temperature. With these measurements MnB₄ was identified to be a semiconductor.