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arXiv · 0908.1299

Magnetic field dependence of the antiferromagnetic phase transitions in Co-doped YbRh_2Si_2

C. Klingner·C. Krellner·C. Geibel
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Abstract

We present first specific-heat data of the alloy Yb(Rh_(1-x)Co_x)_2Si_2 at intermediate Co-contents x=0.18, 0.27, and 0.68. The results already point to a complex magnetic phase diagram as a function of composition. Co-doping of YbRh_2Si_2 (T_N^{x=0}=72 mK) stabilizes the magnetic phase due to the volume decrease of the crystallographic unit cell. The magnetic phase transitions are clearly visible as pronounced anomalies in C^{4f}(T)/T and can be suppressed by applying a magnetic field. Going from x=0.18 to x=0.27 we observe a change from two mean-field (MF) like magnetic transitions at T_N^{0.18}=1.1 K and T_L^{0.18}=0.65 K to one sharp λ-type transition at T_N^{0.27}=1.3 K. Preliminary measurements under magnetic field do not confirm the field-induced first-order transition suggested in the literature. For x=0.68 we find two transitions at T_N^{0.68}=1.14 K and T_L^{0.68}=1.06 K.

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C. Klingner, C. Krellner, C. Geibel. 2009-08-10. Magnetic field dependence of the antiferromagnetic phase transitions in Co-doped YbRh_2Si_2. https://doi.org/10.1088/1742-6596%2F200%2F1%2F012089

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