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Kondo effect and quantum critical point in Mn(1−x)CoxSi

Published in Journal of Physics: Conference Series. 2010, vol. 200, no. 3, p. 032076
Abstract We report magnetic, transport and neutron diffraction studies of the solid solution Mn1−xCoxSi. For the Mn rich compounds, a sharp decrease of the Curie temperature is observed upon cobalt doping and neutron elastic scattering shows that the helimagnetic order of MnSi persists up to x = 0.06 with a shortening of the helix period. For higher Co concentrations (0.06 < x < 0.90), the Weiss temperature changes sign and the system enters an antiferromagnetic state upon cooling (TN=9K for x = 0.50). In this doping range, the antiferromagnetic coupling leads to a Kondo effect marked by a minimum in the resistivity. This scenario is supported by the scaling of the magnetoresistance with a TK ≈ 6.5 K, close to the change in curvature of the resistivity and in agreement with the Weiss temperature from magnetic susceptibility. The sign change of the Weiss temperature and the transition from a helimagnetic to an antiferromagnetic ground state, with increasing the Co doping, point toward the existence of a quantum critical point at the composition Mn0.94Co0.06Si.
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TEYSSIER, Jérémie et al. Kondo effect and quantum critical point in Mn(1−x)CoxSi. In: Journal of Physics: Conference Series, 2010, vol. 200, n° 3, p. 032076. doi: 10.1088/1742-6596/200/3/032076 https://archive-ouverte.unige.ch/unige:35129

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Deposited on : 2014-03-31

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