Remarkable magnetostructural coupling around the magnetic transition in CeCo0.85Fe0.15Si
Remarkable magnetostructural coupling around the magnetic transition in CeCo0.85Fe0.15Si
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CeCo0.85Fe0.15Si 中磁转变周围存在显着的磁结构耦合
DOI：
10.1088/0953-8984/28/34/346003
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
C. Geibel
中科院分区：
文献类型：
--
作者：
V. Correa;D. Betancourth;J. Sereni;N. Caroca Canales;C. Geibel
我们详细研究了CeCo0.85Fe0.15Si在高磁场(高达16特斯拉)下的磁性能，测量了不同的物理性能，如比热、磁化强度、电阻率、热膨胀和磁致伸缩。CeCo0.85Fe0.15Si在TN≈6.7K时变为反铁磁性，但比热中的宽尾(在TX≈13K开始)先于该二级相变。在电阻率的温度导数中也可以观察到这条尾巴。然而，尤其值得注意的是热膨胀系数，在那里它采取以Tx为中心的大凸起的形式。强磁场实际上会冲刷掉电阻率中的那条尾巴。但令人惊讶的是，热膨胀系数的凸起变成了一个非常明显的峰值，完全从Tn的磁相变中分离出来。同时，在Tn以上，磁阻也由负向正转变。当磁相互作用占主导地位时，在低温下(ΔLL(16T)∼4×10−4，2K)磁致伸缩是显著的和不可逆的。在低T下观察到的磁致伸缩随磁场的大幅跳跃可能是弱的正在进行的超磁相变的标志。综上所述，结果表明晶格效应对这些合金中磁序的发展具有重要意义。
We report a detailed study of the magnetic properties of CeCo0.85Fe0.15Si under high magnetic fields (up to 16 Tesla) measuring different physical properties such as specific heat, magnetization, electrical resistivity, thermal expansion and magnetostriction. CeCo0.85Fe0.15Si becomes antiferromagnetic at TN≈6.7 K. However, a broad tail (onset at TX≈13 K) in the specific heat precedes that second order transition. This tail is also observed in the temperature derivative of the resistivity. However, it is particularly noticeable in the thermal expansion coefficient where it takes the form of a large bump centered at TX. A high magnetic field practically washes out that tail in the resistivity. But surprisingly, the bump in the thermal expansion coefficient becomes a well pronounced peak fully split from the magnetic transition at TN. Concurrently, the magnetoresistance also switches from negative to positive above TN. The magnetostriction is considerable and irreversible at low temperature (ΔLL(16 T)∼4×10−4 at 2 K) when the magnetic interactions dominate. A broad jump in the field dependence of the magnetostriction observed at low T may be the signature of a weak ongoing metamagnetic transition. Taking altogether the results indicate the importance of the lattice effects on the development of the magnetic order in these alloys.