Li(CdMn)P: a new cadmium based diluted ferromagnetic semiconductor with independent spin charge doping

摘要

We report a new diluted ferromagnetic semiconductor Li1+y(Cd,Mn)P, wherein carrier is doped via excess Li while spin is doped by isovalence substitution of Mn²⁺ into Cd²⁺. The extended Cd 4d-orbitals lead to more itinerant characters of Li1+y(Cd,Mn)P than that of analogous Li1+y(Zn,Mn)P. A higher Curie temperature of 45 K than that for Li1+y(Zn,Mn)P is obtained in Li1+y(Cd,Mn)P polycrystalline samples by Arrott plot technique. The p-type carriers are determined by Hall effect measurements. The first principle calculations and X-ray diffraction measurements indicate that occupation of excess Li is at Cd sites rather than the interstitial site. Consequently holes are doped by excess Li substitution. More interestingly Li1+y(Cd,Mn)P shows a very low coercive field (<100 Oe) and giant negative magnetoresistance (~80%) in ferromagnetic state that will benefit potential spintronics applications.