No abstract

Recent studies have dealt with the electronic and magnetic ground state properties of the tetraboride material MnB 4 . So far, however, the ground state properties could not be established unambiguously. Therefore, here we present an experimental study on single-crystalline MnB 4 by means of resistivity and magnetization measurements. For this, we have developed a sample holder that allows four-point ac resistivity measurements on these very small (∼ 100 µm) samples. With our data we establish that the electronic ground state of MnB 4 is intrinsically that of a pseudo-gap system, in agreement with recent band structure calculations. Furthermore, we demonstrate that the material does neither show magnetic order nor a behavior arising from the vicinity to a magnetically ordered state, this way disproving previous claims.