Manipulating magnetism and transport properties of EuCd2P2 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 ${\mathrm{EuCd}}_{2}{\mathrm{P}}_{2}$, which is transformed from an A-type antiferromagnet $({T}_{\mathrm{N}}=11\phantom{\rule{0.16em}{0ex}}\mathrm{K})$ exhibiting colossal magnetoresistance into a ferromagnet $({T}_{\mathrm{C}}=47\phantom{\rule{0.16em}{0ex}}\mathrm{K})$ with metallic behavior. The dramatic alteration results from a low hole concentration of ${10}^{19}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}3}$ induced by changing the growth conditions. Electronic structure and total energy calculations confirm the tunability of magnetism with a small carrier concentration for ${\mathrm{EuCd}}_{2}{\mathrm{P}}_{2}$. 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 ${\mathrm{EuCd}}_{2}{\mathrm{P}}_{2}$ make it a potential candidate for spintronics.