Ba(Zn1-2x Mnx Cux)2As2: A bulk form diluted ferromagnetic semiconductor with Mn and Cu codoping at Zn sites

Abstract

We report the synthesis and characterization of a bulk form diluted magnetic semiconductor Ba(Zn1-2x Mnx Cux)2 As2 with the crystal structure identical to that of "122" family iron based superconductors and the antiferromagnet BaMn2 As2. No ferromagnetic order occurs with (Zn, Mn) or (Zn, Cu) substitution in the parent compound BaZn2 As2. Only when Zn is substituted by both Mn and Cu simultaneously, can the system undergo a ferromagnetic transition below TC ∼ 70K, followed by a magnetic glassy transition at Tf ∼ 35K. AC susceptibility measurements for Ba(Zn0.75 Mn0.125 Cu0.125)2 As2 reveal that T f strongly depends on the applied frequency with and a DC magnetic field dependence of, demonstrating that a spin glass transition takes place at T f. As large as -53% negative magnetoresistance has been observed in Ba(Zn1-2x Mnx Cux)2 As2, enabling its possible application in memory devices.