Mediated ferromagnetism in ZnO nanorods with heavily codoped MnFe

The ferromagnetic properties are investigated in single crystal ZnO nanorods with heavy codoping of 28 at. % Mn and 1 at. % Fe fabricated by vapor phase transport. The electron energy loss spectroscopy and x-ray photoelectron spectroscopy confirmed that Mn and Fe dopants are, respectively, +2 and +3 valence states, where Raman scattering exhibited additional peaks at 308 cm−1, 458 cm−1, 480 cm−1, 504 cm−1, 516 cm−1, 530 cm−1, and 569 cm−1, associated with MnFe dopants. Compared with undoped and Mn doped ZnO nanostructures, the MnFe-codoped ZnO nanorods are strongly ferromagnetic below Tc of 39 K and around room temperature. The ferromagnetic behavior can be mainly attributed to the carrier-mediated Ruderman–Kittel–Kasuya–Yosida mechanism below Tc and the defect-induced bound magnetic polaron mechanism around room temperature.