Abstract
We report the synthesis and characterization of a bulk form diluted magnetic semiconductor Ba(Zn1−2xMnxCux)2As2 with the crystal structure identical to that of “122” family iron based superconductors and the antiferromagnet BaMn2As2. No ferromagnetic order occurs with (Zn, Mn) or (Zn, Cu) substitution in the parent compound BaZn2As2. Only when Zn is substituted by both Mn and Cu simultaneously, can the system undergo a ferromagnetic transition below TC ~ 70 K, followed by a magnetic glassy transition at Tf ~ 35 K. AC susceptibility measurements for Ba(Zn0.75Mn0.125Cu0.125)2As2 reveal that Tf strongly depends on the applied frequency with and a DC magnetic field dependence of , demonstrating that a spin glass transition takes place at Tf. As large as −53% negative magnetoresistance has been observed in Ba(Zn1−2xMnxCux)2As2, enabling its possible application in memory devices.
Highlights
We report the synthesis and characterization of a bulk form diluted magnetic semiconductor Ba(Zn1−2xMnxCux)2As2 (0.025 ≤ x ≤ 0.2) with the crystal structure identical to that of “122” family iron based superconductors and the antiferromagnet BaMn2As2
The highest Curie temperature, TC, of (Ga, Mn)As films has been reported as 200 K7
Many novel DMSs that are derivatives of Fe-based superconductors have been reported[8,9,10,11,12,13,14,15,16,17,18,19]. It has been shown from NMR20 and μSR measurements that the ferromagnetism in (BaK)(ZnMn)2As29, Li(Zn, Mn)As10, (La, Ba)(Zn, Mn)AsO12 and Li(Zn, Mn)P21 are homogeneous, i.e., the long range ferromagnetic ordering is arising from the Mn atoms doped at Zn sites, instead of Mn related magnetic impurities
Summary
We report the synthesis and characterization of a bulk form diluted magnetic semiconductor Ba(Zn1−2xMnxCux)2As2 (0.025 ≤ x ≤ 0.2) with the crystal structure identical to that of “122” family iron based superconductors and the antiferromagnet BaMn2As2. Seeking for new DMS materials that have higher chemical solubility of magnetic atoms and whose carrier density and spin density can be controlled separately may be helpful to improve TC and understand the mechanism of the ferromagnetic ordering[8]. ΜSR results demonstrated that these bulk form DMSs share the same mechanism for the ferromagnetic ordering as that of (Ga, Mn)As22 These bulk form DMSs have the advantages of decoupled spin and carrier doping, and the carrier densities can be controlled and tuned, which overcomes the low carrier densities encountered in II-VI DMS23. Future work is needed to gain deeper understanding of the magnetic behavior of this system and achieve higher TC values
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