Doping Effects on the two-dimensional Spin Dimer Compound $SrCu_2(BO_3)_2$

TL;DR

This study investigates how doping SrCu$_2$(BO$_3$)$_2$ with various elements affects its magnetic properties, revealing suppression of the spin gap under magnetic fields without inducing superconductivity.

Contribution

It provides experimental data on doping effects on the spin gap and magnetic behavior of SrCu$_2$(BO$_3$)$_2$, expanding understanding of its magnetic properties.

Findings

Doping maintains the isostructural nature of the compound.

The spin gap is strongly suppressed by magnetic fields.

No superconductivity observed in doped samples.

Abstract

A series of compounds M$_{0.1}$Sr$_{0.9}$Cu$_2$(BO$_3$)$_2$ with Sr substituted by M=Al, La, Na and Y were prepared by solid state reaction. XRD analysis showed that these doping compounds are isostructural to SrCu$_2$(BO$_3$)$_2$. The magnetic susceptibility from 1.9K to 300K in an applied magnetic field of 1.0T and the specific heat from 1.9K to 25K in applied fields up to 14T were measured. The spin gap is deduced from the low temperature susceptibility as well as the specific heat. It is found that the spin gap is strongly suppressed by magnetic fields. No superconductivity is observed in all four samples.