Manipulating magnetism and transport properties of ${\mathrm{EuCd}}_2{P}_2$ with a low carrier concentration

Materials that exhibit strongly coupled magnetic order and electronic properties are crucial for both fundamental research and technological applications. However, finding a material that not only shows remarkable magnetoresistive responses but also has an easily tunable ground state remains a challenge. Here, we report successful manipulation of the magnetic and transport properties of ${\mathrm{EuCd}}_2{P}_2$, which is transformed from an A-type antiferromagnet $(T_N=11K)$ exhibiting colossal magnetoresistance into a ferromagnet $(T_C=47K)$ with metallic behavior. The dramatic alteration results from a low hole concentration of ${10}^{19}c{m}^{-3}$ induced by changing the growth conditions. Electronic structure and total energy calculations confirm the tunability of magnetism with a small carrier concentration for ${\mathrm{EuCd}}_2{P}_2$. It is feasible to switch between the magnetic states by using field-effect to control the carrier density, thereby changing the magneto-electronic response. The controllable magnetism and electrical transport of ${\mathrm{EuCd}}_2{P}_2$ make it a potential candidate for spintronics.