| Diluted magnetic semiconductors(DMSs) have attracted increasing attention because of their potential applications in spintronics. Resently, a series of new bulk DMSs were synthezied by doping in 111, 122 and 1111 phases of iron-based superconductors, which shed light on the DMSs research. In this paper,we have synthesized four systems of 1111 phases of DMSs, i.e.(La1-x Srx)(Ag0.925Mn0.075)SO,(La1-x Bax)(Ag0.925Mn0.075)SO,(Y1-x Srx)(Cu0.925Mn0.075)SOand(Y1-x Bax)(Cu0.925Mn0.075)SO(x=0, 0.025, 0.05, 0.075 and 0.1) by solid state method. And the structure and electrical, magnetic and optical properties have been investigated.Some interesting phenomena are found(Such as the change of the Curie temperature Tc and band-gap energy Eg). The results are helpful to clarify the intrinsic mechanism of the DMSs, and will provide new insights on the fabrication and application of devices based on these materials. The detail information is as following:1. All the four series of new bulk DMSs were prepared in a glove box with nitrogen atmosphere. After sealed in glass tubes, they are sintered in box-typed furnace.(La1-x Bax)(Ag0.925Mn0.075)SO and(La1-x Srx)(Ag0.925Mn0.075)SO(x=0, 0.025,0.05, 0.075 and 0.1) were heated up to 1100℃ and kept at the temperature for about2000 minutes while(Y1-x Bax)(Cu0.925Mn0.075)SO and(Y1-x Srx)(Cu0.925Mn0.075)SO(x=0, 0.05, 0.075 and 0.1) were just heated up to 900℃ and kept at the temperature for the same period.2. In order to choose the better samples for further opitical study, the synthesized samples were investigated firstly. It was found that all the peaks can be well indexed based on the P4/nmm space group with tetragonal Zr Cu Si As-type structure. The R-T curves of the samples in the range of 3.5K~295K show semiconductive properties except for that of(Y1-x Srx)(Cu0.925Mn0.075)SO(x=0.1),which presents a metallic character below 240 K. Temperature dependences of dc magnetic susceptibility were also measured from 2K to 295 K under FC and ZFC. It is found tnat(Y1-x Srx)(Cu0.925Mn0.075)SO(x=0.075 and 0.1) exhibit ferromagnetic order with Curie temperature Tc =46.1K and 47.8K. However,(La1-x Bax)(Ag0.925Mn0.075)SO exhibits ferromagnetic order only with Tc =11.5K.3. Thus we choose(La1-x Srx)(Ag0.925Mn0.075)SO and(Y1-x Srx)(Cu0.925Mn0.075)SO for PL spectrum analyses, which including peak position, peak width, emission intensity and band gap. From the PL spectrums of(La1-x Srx)(Ag0.925Mn0.075)SO, we find that the band gap is 3.95 e V, 3.18 e V and 3.12 e V corresponding to x=0.025,0.05 and 0.1 respectively. Differently, the band gap is almost unchanged(2.2e V) with the dopant addition accordint to the PL spectrums of(Y1-x Srx)(Cu0.925Mn0.075)SO system.We suggest that some more techniques should be used to study the opitical properties of DMSs. |
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