Abstract
The critical behavior near the continuous paramagnetic to ferromagnetic transition in a single crystal of has been determined based on high-resolution bulk magnetization data near ∼ 167 K, where long-range order is established in the Co sublattice. Scaling equation of state analysis and the Kouvel-Fisher method under a moderate applied magnetic field yielded critical exponents (, ), consistent with the = 3, = 3 Heisenberg model of short-range interactions. Calculation of the Rhodes-Wohlfarth ratio confirmed that a localized rather than itinerant description of the Co moments is appropriate in the ferromagnetic region of the sample. The critical susceptibility exponent γ was found to decrease systematically from the Heisenberg model value toward the mean-field model value as the maximum applied magnetic field considered in the analysis was increased above 2 T. The phenomenon is discussed in terms of mixed exchange mechanisms due to the coexistence of and magnetic sublattices and ordered clusters in the paramagnetic region.
4 More- Received 5 August 2014
- Revised 5 October 2014
DOI:https://doi.org/10.1103/PhysRevB.90.174404
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