The synthesis and characterization of 1111-type diluted magnetic semiconductors (La_(1-x)Sr_x)(Zn_(1-x)TM _x)AsO (TM = Mn, Fe, Co)

摘要

The doping effect of Sr and transition metals Mn, Fe, Co into the direct-gap semiconductor LaZnAsO has been investigated. Our results indicate that the single phase ZrCuSiAs-type tetragonal crystal structure is preserved in (La_(1-x)Sr_x)(Zn_(1-x)TM_x)AsO (TM = Mn, Fe, Co) with the doping level up to. While the system remains semiconducting, doping with Sr and Mn results in ferromagnetic order with, and doping with Sr and Fe results in a spin-glass-like state below with a saturation moment of ～0.02 μB/Fe, an order of magnitude smaller than the ～0.4 μB/Mn of Sr- and Mn-doped samples. The same type of magnetic state is observed neither for (Zn,Fe) substitution without carrier doping, nor for Sr- and Co-doped specimens.