Kondo effect and impurity interactions in the resistivity of diluteZnMn alloys
Kondo effect and impurity interactions in the resistivity of diluteZnMn alloys
复制标题
稀锌锰合金电阻率中的近藤效应和杂质相互作用
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
E. Wassermann
中科院分区：
文献类型：
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作者：
J. Kästner;E. Wassermann
在0.05 - 14 K温度范围内，研究了稀相ZnMn合金（c=1.7-2400 ppmMn）的电阻率。对于最稀释的样品，发现了单杂质近藤行为，可以用哈曼公式（TK =0.9 K，S=3/2）很好地描述。当T <50 mK时，T_2定律的θR= 0.3K。在稀释极限下，近藤斜率为−（1/c）d（Δρ）/d（logT）=3.7±0.2 µΩ-cm/at % dec。在浓度更高的合金中，斜率随着c的增加而减小，近藤电阻率的类似lnT的变化大致在温度TW（c）附近终止，TW与Mn杂质之间的平均Ruderman-Kittel-Kasuya-Yosida（RKKY）相互作用强度有关。对于20 ppm ≤c ≤ 1000 ppm，低温下电阻率略有下降，并在Tm（c）处观察到宽范围的电阻率最大值，其中Tm ‡ c0.7。当T2 <Tm时，电阻率与T成线性关系，而对于浓度最高的合金，在可达到的最低温度下测量了aT 3/2或T2的关系。通过对ZnMn的超导转变温度Tc（c）的研究，得到了临界Mn浓度ccr =18 ppm。低于0.3 K的Tc的浓度依赖性表明存在近藤效应，虽然杂质相互作用也可能影响Tc在这个温度范围内。
The electrical resistivity of diluteZnMn alloys (c=1.7–2400 ppm Mn) has been investigated in the temperature range from 0.05 to 14 K. For the most dilute sample, single-impurity Kondo behavior is found, well described by the Hamann formula withTK=0.9 K,S=3/2. ForT<50 mK, aT2 law with θR=0.3 K is expected. In the dilute limit the Kondo slope is −(1/c)d(Δρ)/d(logT)=3.7±0.2 µΩ-cm/at % dec. In the more highly concentrated alloys, the slope decreases with increasing c and the lnT-like variation of the Kondo resistivity roughly terminates near a temperatureTW(c),TW being related to the average Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction strength between the Mn impurities. For 20 ppm ≤c ≤ 1000 ppm, the resistivity slightly decreases at low temperatures and a broad resistivity maximum is observed atTm(c), withTm ∝c0.7. ForT 2<Tm, the resistivity dependence is linear inT, and for the most concentrated alloy aT3/2 orT2 dependence is measured at the lowest temperatures attainable. The investigation of the transition temperatureTc(c) to superconductivity ofZnMn results in a critical concentrationccr=18 ppm Mn. The concentration dependence ofTc below 0.3 K suggests the presence of the Kondo effect, although impurity interactions may also influenceTc in this temperature range.