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

TL;DR

This study investigates how in-plane chemical substitutions in SrCu$_2$(BO$_3$)$_2$ affect its magnetic properties, revealing a decrease in the spin gap without inducing superconductivity.

Contribution

It provides systematic synthesis and characterization of in-plane substituted SrCu$_2$(BO$_3$)$_2$ compounds, highlighting the impact on magnetic properties and spin gap behavior.

Findings

Spin gap decreases with increasing substitution content

Substituted compounds remain single-phase materials

No superconductivity observed in substituted samples

Abstract

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 solid state reaction. X-ray diffraction measurements reveal that these compounds are single-phase materials and their in-plane lattice parameter depends systematically on the substituting content $x$. The magnetic susceptibility in different magnetic fields, the magnetization at different temperatures, and the resistivity at room temperature were measured, respectively. It is found that the spin gap deduced from the magnetic susceptibility measurements decreases with increasing of $x$ in both Cu- and B-site substitution. No superconductivity was found in these substituted compounds.