Complex single-site magnetism and magnetotransport in single-crystalline Gd${}_2$AlSi${}_3$

Abstract

We present a detailed investigation of single-crystal samples of the magnetic compound Gd${}_2$AlSi${}_3$, which crystallizes in the $\hat{I}\pm$-ThSi${}_2$ type tetragonal structure. We report the temperature and magnetic field dependence of the magnetic susceptibility, magnetization, heat capacity, electrical resistivity, and magnetoresistance for magnetic fields applied along both the tetragonal $c$-axis and in the basal $ab$-plane. X-ray diffraction measurements confirm a centrosymmetric, $I{4}_1/amd$ space group of the crystal structure. Despite single-site occupancy of the Gd position in this tetragonal structure, we identify two successive antiferromagnetic phase transitions at Neél temperatures 32~K and 23~K via magnetic susceptibility, heat capacity and transport measurements, as well as a complex magnetic interaction with a magnetic anisotropy that plays an important role in the direction-dependent transport response. Our identification of multiple magnetic phases in Gd${}_2$AlSi${}_3$, where Gd is the only magnetic species, helps to elucidate the field-induced skyrmionic behavior in the Gd-based intermetallic compounds.

10 pages, 9 figures