In-plane substitution effect on the magnetic properties of two-dimensional Spin-gap system SrCu$_2$(BO$_3$)$_2$

摘要

A series of in-plane substituted compounds, including Cu-site(SrZn$_x$Cu$_{2-x}$(BO$_3$)$_2$), and B-site(SrCu$_2$(Si$_x$B$_{1-x}$O$_3$)$_2$) substitution, were synthesized by solidstate reaction. X-ray diffraction measurements reveal that these compounds aresingle-phase materials and their in-plane lattice parameter dependssystematically on the substituting content $x$. The magnetic susceptibility indifferent magnetic fields, the magnetization at different temperatures, and theresistivity at room temperature were measured, respectively. It is found thatthe spin gap deduced from the magnetic susceptibility measurements decreaseswith increasing of $x$ in both Cu- and B-site substitution. Nosuperconductivity was found in these substituted compounds.