Ferromagnetic behavior induced by La-doping in SrCo2As2†
Abstract
Recently, stripe antiferromagnetic spin fluctuations have been observed in SrCo2As2, which are similar to those found in AFe2As2 superconductors. It is interesting to tune the magnetic properties of this compound to induce superconductivity by chemical doping or applied pressure. Here we present careful chemical doping studies on SrCo2As2 by doping the element La on the Sr sites. We found that a dramatic alteration of the magnetic behavior (from paramagnetism to ferromagnetism) was induced by the incorporation of traces of La (2.5%). The results show that ferromagnetic order is preferred over A-type AFM or stripe-type AFM order when SrCo2As2 is electron-doped. On this basis, in order to regulate its magnetic ground state with the aim of inducing superconductivity, hole-doping may be superior to electron-doping. Furthermore, an unusual magnetic phase diagram between SrCo2As2 and LaCo2As2 is also presented in this work.