Magnetic field dependence of the antiferromagnetic phase transitions in Co-doped YbRh<sub>2</sub>Si<sub>2</sub>
Christoph Klingner; Cornelius Krellner; Christoph Geibel; Christoph Klingner; Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany; Cornelius Krellner; Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany; Christoph Geibel; Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
Журнал:
Journal of Physics: Conference Series
Дата:
2010-01-01
Аннотация:
We present first specific-heat data of the alloy Yb(Rh<sub>1−x</sub>Co<sub>x</sub>)<sub>2</sub>Si<sub>2</sub> 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<sub>2</sub>Si<sub>2</sub> (T<sup>x0</sup><sub>N</sub> 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<sup>4f</sup>(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<sup>0.18</sup><sub>N</sub> 1.1K and T<sup>0.18</sup><sub>L</sub> 0.65 K to one sharp λ-type transition at T<sup>0.27</sup><sub>N</sub> 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<sup>0.68</sup><sub>N</sub> 1.14 K and T<sup>0.68</sup><sub>L</sub> 1.06 K.
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