Uniaxial stress effects on magnetic and electric properties of the ground state in a centrosymmetric magnetic skyrmion host Gd$_2$PdSi$_3$

Abstract

We investigate effects of uniaxial stress to magnetic orders and electrical resistivity of the centrosymmetric magnetic skyrmion compound Gd$_2$PdSi$_3$, which has a hexagonal crystal structure composed of triangular lattice layers of magnetic Gd$^{3+}$ ions. This compound is known to exhibit the triple-$q$ magnetic skyrmion lattice phase with a giant topological Hall effect in the first field induced phase [T. Kurumaji $\textit{et al}$. Science $\textbf{365}$, 914-918 (2019)]. In contrast to the established picture of the field-induced phase, the ground state of this system still remains to be studied. Although previous studies reported the existence of the incommensurate magnetic modulations described by a magnetic modulation wave vector ${\bf q}=(q,0,0)$ where $q\sim 0.14$ and its equivalents, it is still unclear whether the magnetic structure is a single-$q$ structure or a multiple-$q$ structure. In the present study, we performed magnetization, resistivity and neutron diffraction measurements with a compressive uniaxial stress applied perpendicular to the $c$ axis. The observed data revealed that the system did not exhibit anisotropic magnetic and electric properties expected from a single-$q$ magnetic order, suggesting that the magnetic ground state of this system is a multi-$q$ magnetic order.