4 GLYPH<s48> GLYPH<s53> GLYPH<s48> GLYPH<s49> GLYPH<s48> GLYPH<s49> GLYPH<s53> GLYPH<s48> GLYPH<s50> GLYPH<s48> GLYPH<s50> GLYPH<s53> GLYPH<s48> GLYPH<s51> GLYPH<s48> GLYPH<s45>GLYPH<s48> GLYPH<s46>GLYPH<s50> GLYPH<s48> GLYPH<s46>GLYPH<s48> GLYPH<s48> GLYPH<s46>GLYPH<s50> GLYPH<s48> GLYPH<s46>GLYPH<s52> GLYPH<s48> GLYPH<s46>GLYPH<s54> GLYPH<s48> GLYPH<s46>GLYPH<s56> GLYPH<s49> GLYPH<s46>GLYPH<s48> GLYPH<s49> GLYPH<s46>GLYPH<s50> GLYPH<s49> GLYPH<s46>GLYPH<s52> GLYPH<s49> GLYPH<s46>GLYPH<s54> GLYPH<s48> GLYPH<s53>GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s49>GLYPH<s53>GLYPH<s48> GLYPH<s50>GLYPH<s48>GLYPH<s48> GLYPH<s50>GLYPH<s53>GLYPH<s48> GLYPH<s51>GLYPH<s48>GLYPH<s48> GLYPH<s48> GLYPH<s50>GLYPH<s48> GLYPH<s52>GLYPH<s48> GLYPH<s54>GLYPH<s48> GLYPH<s56>GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s49>GLYPH<s50>GLYPH<s48> GLYPH<s48> GLYPH<s53> GLYPH<s48> GLYPH<s49> GLYPH<s48> GLYPH<s49> GLYPH<s53> GLYPH<s48> GLYPH<s50> GLYPH<s48> GLYPH<s45>GLYPH<s48> GLYPH<s46>GLYPH<s51> GLYPH<s48> GLYPH<s45>GLYPH<s48> GLYPH<s46>GLYPH<s50> GLYPH<s53> GLYPH<s45>GLYPH<s48> GLYPH<s46>GLYPH<s50> GLYPH<s48> GLYPH<s45>GLYPH<s48> GLYPH<s46>GLYPH<s49> GLYPH<s53> GLYPH<s45>GLYPH<s48> GLYPH<s46>GLYPH<s49> GLYPH<s48> GLYPH<s45>GLYPH<s48> GLYPH<s46>GLYPH<s48> GLYPH<s53> GLYPH<s48> GLYPH<s46>GLYPH<s48> GLYPH<s48> GLYPH<s48> GLYPH<s46>GLYPH<s48> GLYPH<s53> GLYPH<s48> GLYPH<s46>GLYPH<s49> GLYPH<s48> GLYPH<s48> GLYPH<s46>GLYPH<s49> GLYPH<s53> GLYPH<s32>GLYPH<s66>GLYPH<s97> GLYPH<s48>GLYPH<s46>GLYPH<s53> GLYPH<s75> GLYPH<s48>GLYPH<s46>GLYPH<s53> GLYPH<s70>GLYPH<s101> GLYPH<s50> GLYPH<s65>GLYPH<s115> GLYPH<s50> GLYPH<s32>GLYPH<s90>GLYPH<s110>GLYPH<s61>GLYPH<s54>GLYPH<s37> GLYPH<s32>GLYPH<s90>GLYPH<s110>GLYPH<s61>GLYPH<s56>GLYPH<s37> GLYPH<s32>GLYPH<s77>GLYPH<s110>GLYPH<s61>GLYPH<s50>GLYPH<s37> GLYPH<s32>GLYPH<s77>GLYPH<s110>GLYPH<s61>GLYPH<s52>GLYPH<s37> GLYPH<s32>GLYPH<s77>GLYPH<s110>GLYPH<s61>GLYPH<s56>GLYPH<s37> GLYPH<s32> GLYPH<s82> GLYPH<s72> GLYPH<s32>GLYPH<s40> GLYPH<s49> GLYPH<s48> GLYPH<s45>GLYPH<s57> GLYPH<s32>GLYPH<s109> GLYPH<s51> GLYPH<s47>GLYPH<s67> GLYPH<s41> GLYPH<s40> GLYPH<s97>GLYPH<s41> GLYPH<s32>GLYPH<s66>GLYPH<s97> GLYPH<s48>GLYPH<s46>GLYPH<s53> GLYPH<s75> GLYPH<s48>GLYPH<s46>GLYPH<s53> GLYPH<s70>GLYPH<s101> GLYPH<s50> GLYPH<s65>GLYPH<s115> GLYPH<s50> GLYPH<s32>GLYPH<s77> GLYPH<s110>GLYPH<s61>GLYPH<s56>GLYPH<s37> GLYPH<s32>GLYPH<s90>GLYPH<s110>GLYPH<s61>GLYPH<s52>GLYPH<s37> GLYPH<s77>GLYPH<s110> GLYPH<s45> GLYPH<s100> GLYPH<s111> GLYPH<s112> GLYPH<s105>GLYPH<s110> GLYPH<s103> GLYPH<s32>GLYPH<s32>GLYPH<s32>GLYPH<s32>GLYPH<s32> GLYPH<s32>GLYPH<s32>GLYPH<s32>GLYPH<s120>GLYPH<s61>GLYPH<s48>GLYPH<s46>GLYPH<s48>GLYPH<s56> GLYPH<s32> GLYPH<s32> GLYPH<s77>GLYPH<s40>GLYPH<s101> GLYPH<s109>GLYPH<s117> GLYPH<s47>GLYPH<s109>GLYPH<s111> GLYPH<s108>GLYPH<s41> GLYPH<s84> GLYPH<s40>GLYPH<s75> GLYPH<s41> GLYPH<s40> GLYPH<s98>GLYPH<s41> GLYPH<s84> GLYPH<s32>GLYPH<s40> GLYPH<s75>GLYPH<s41> GLYPH<s32> GLYPH<s77>GLYPH<s82>GLYPH<s32>GLYPH<s40>GLYPH<s37>GLYPH<s41> GLYPH<s84> GLYPH<s32>GLYPH<s40> GLYPH<s75>GLYPH<s41> GLYPH<s32>GLYPH<s52> GLYPH<s32>GLYPH<s84> GLYPH<s32>GLYPH<s54> GLYPH<s32>GLYPH<s84> GLYPH<s32>GLYPH<s57> GLYPH<s32>GLYPH<s84> GLYPH<s49> GLYPH<s48> GLYPH<s32> GLYPH<s109> GLYPH<s49> GLYPH<s49> GLYPH<s48> GLYPH<s55> GLYPH<s53> GLYPH<s51> GLYPH<s50> GLYPH<s52> GLYPH<s54> GLYPH<s56> GLYPH<s57> FIG. 4: (color online) Scanning electron microscopy image of Zn-doped sample with x=0.10. The numbers in the image correspond to the typical grains which we chose randomly to carry out the measurement of energy dispersive x-ray. From the EDX data, the compositions of Zn in different grains could be obtained and shown respectively in Table I. FIG. 5: (color online) (a) Temperature dependence of Hall co- efficient R H = ρ xy /H measured at 9 T for the undoped, three Mn-doped and two Zn-doped samples. One can see that by doping more Mn into the system the positive Hall coefficient R H becomes smaller, indicating the doping of holes into the system. While Zn-doping does not change the Hall coeffi- cient too much. (b) MR of the Mn-doped samples, a negative MR was observed here. Inset of (b) shows the temperature dependence of DC magnetization of the undoped, Mn-doped and Zn-doped sample. The M(T) relation can be described by the Curie-Weiss law (see text). IV. DISCUSSION electrons. Fig.5(b) presents the MR of the Mn-doped sample with x = 0.08, a clear negative MR effect was observed at low temperatures. This negative MR can be easily understood as due to the enhanced electron- spin scattering: doping Mn induces more and more mag- netic centers which have stronger magnetic moment com- pared to that of Fe $^{2+}$. This argument is supported by the enhanced magnetic susceptibility in the Mn-doped samples. As shown in the inset of Fig.5(b), the tem- perature dependence of DC magnetization of the Mn- doped sample can be described nicely by the Curie-Weiss law χ = χ$_{0}$ + C/ ( T + T$_{N}$ ) with C = µ$_{0}$µ 2 $_{J}$/ 3 k$_{B}$ , yield- ing µ$_{J}$ = 0.482 µ$_{B}$ /(Fe) in the undoped sample, 0.645 µ$_{B}$ /(Fe+Mn) in the Mn-doped (x=0.08) sample, 0.362 µ$_{B}$ /(Fe+Zn) in the Zn-doped (x=0.04) sample. Assum- ing that each Fe-site has also 0.482 µ$_{B}$ in the Mn-doped sample, then each Mn-site contributes about 2.58 µ$_{B}$ . Zn-doped sample naturally lowers down the paramag- netic susceptibility, suggesting that nonmagnetic impuri- ties have been formed. Although it is still under debate whether the AF order is due to the localized moment or itinerant electrons, it is qualitatively correct to make an assessment that the increase of the value of constant ” C ” in the Curie-Weiss law could be attributed to the en- hancement of local magnetic moments upon Mn-doping, this argument is also consistent with the negative mag- netoresistivity data (Kondo-like scattering). Finally we summarize the main results in Fig.6. For Mn-doped samples, as the doping concentration in- creases, T$_{c}$ decreases quickly with a rate of Δ T$_{c}$ /Mn-1% = - 4.2 K, while for the Zn-doped samples the variation of T$_{c}$ is rather small which could be termed as negligible. According to the Abrikosov-Gorkov formula, 37 if the im- purities act as strong pair breakers, the T$_{c}$ suppression due to pair breaking is essentially related to the impu- rity scattering rate k$_{B}$ Δ T$_{c}$ ≈ π ¯ h/ 8 τ$_{imp}$ ∝ ρ$_{0}$ , where ρ$_{0}$ is the residual resistivity and can be roughly expressed as m $^{∗}$/ne $^{2}$τ$_{imp}$ in the single band description with n the charge carrier density, m ∗ the effective mass. Therefore we present also the doping dependence of ρ$_{0}$ in Fig.6. The enhancement of ρ$_{0}$ is much stronger for the Mn- doped samples compared with the Zn-doped ones, which indicates different impurity scattering effects in the two