Influence of europium doping on magnetic properties of 3D topological semimetal Cd$_{3}$As$_{2}$ from ESR data

Influence of weak doping by rare-earth elements on magnetic and transport properties of a 3D topological semimetal Cd$_{3}$As$_{2}$ was studied experimentally. In particular, the doping by europium causes to change of the magnetoresistance sign from positive to negative. First measurements of electron spin resonance and magnetic susceptibility have shown that there are two types of Eu$^{2+}$ magnetic ions that occupy the positions of cadmium ions and tetrahedral vacancies and form the ferromagnetic and antiferromagnetic phases, respectively. These facts give an evidence of small-scaled phase separation and a transformation of the Dirac semimetal to a Weyl semimetal induced by magnetic impurities.