Magnetic and transport properties of the narrow-gap semiconductor Yb5Si4
Magnetic and transport properties of the narrow-gap semiconductor Yb5Si4
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窄带隙半导体Yb5Si4的磁性和输运特性
DOI：
10.1088/1742-6596/592/1/012092
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Shinji Michimura
中科院分区：
文献类型：
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作者：
Masashi Kosaka;Shingo Ottomo;Ayumi Machida;Tomoyuki Kirigane;Ryosuke Numakura;Susumu Katano;Shinji Michimura
报道了二元化合物Yb5Si4的合成和基本性质.在这种化合物中，Yb离子占据三个不同的晶体位置，其多重性由Yb 1：Yb 2：Yb 3 = 1：2：2表示。计算的有效磁矩和磁熵可以用Yb的价态比（Yb3+：Yb2 += 2：3）来解释。这一结果表明Yb3+离子可能占据Yb2或Yb3位。Yb5Si4在TN = 1.7K时发生反铁磁转变.在高于TN的比热随温度的变化关系中，观察到了延长的高温尾。Yb 5 Si 4的磁化率在2.3K附近也出现了宽的最大峰，对应于比热异常。我们认为这些异常可能源于低维Yb3+网络引起的磁涨落。Yb5Si4的电阻率测量揭示了其在所有温度下的半导体行为.用热激活模型估算了室温下的小能隙Δ= 430 K。能隙随温度的降低而逐渐减小，在低温下可达到约3K。
We report the synthesis and basic properties of the binary compound Yb 5 Si 4. In this compound, Yb ions occupy three different crystallographic sites, the multiplicity of which is represented by Yb1: Yb2: Yb3= 1: 2: 2. The estimated effective magnetic moment and magnetic entropy can be explained by the proportion of Yb valence states, Yb 3+: Yb 2+= 2: 3. This result suggests the possibility that Yb 3+ ions occupy either Yb2 or Yb3 site. Yb 5 Si 4 undergoes an antiferromagnetic transition at T N= 1.7 K. The extended high temperature tail in the temperature dependence of the specific heat just above T N has been observed. Yb 5 Si 4 also exhibits the broad maximum peak around 2.3 K in the magnetic susceptibility, corresponding to the specific heat anomaly. We propose that these anomalies are possible to originate from magnetic fluctuations caused by low-dimensional Yb 3+ networks. Electrical resistivity measurements on Yb 5 Si 4 reveal semiconducting behavior at all temperatures. The small energy gap Δ= 430 K has been obtained at room temperature estimated by the thermal activation model. The energy gap gradually decreases with decreasing temperature, and reaches about 3 K at low temperatures.