Effect of Zn substitution on the magnetic properties of Skyrmion Cu$_{2}$OSeO$_{3}$

There is a considerable interest in the new magnetic state, the ``Skyrmion state (A-phase),'' whose magnetic properties have a remarkable characteristic as a vortex-like spin orientation. The polycrystalline (Cu$_{\mathrm{1-x}}$Zn$_{\mathrm{x}})_{2}$OSeO$_{3}$ (x$=$0 to 0.20) samples were synthesized using solid state reaction method and studied by X-ray diffraction, X-ray absorption spectra and magnetic measurements. Variation of lattice constant with Zn doping follows the Vegard's law which signifies the successful substitution of Zn in place of Cu up to x less than 0.20. The Cu L$_{2,3}$ spectra show 2$+$ valence state for all samples. The Curie temperature decrease with Zn doping indicate the ferrimagnetic ordering is gradually suppressed. Moreover, we have notice another magnetic phase for the doping level x between 0.05 and 0.2, whose magnetic transition also shifted to low temperature for higher Zn doping. The H-T magnetic phase diagrams of the samples from ac susceptibility have been established with increasing Zn doping. The explanations for the observations of doping effects on the A-phase of Skyrmion Cu$_{2}$OSeO$_{3}$ will be discussed.