ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The magnetic behavior of Ni(SCN)2 has been studied at low temperatures for the first time. A Curie–Weiss fit, χM=C/(T−θ), to the susceptibility between 100 and 300 K yields g=2.13±0.01 (S=1) and θ=39.8±1.4 K. Systematic curvature in χ−1 vs T is evident, however. Despite the large positive θ Ni(SCN)2 appears to order antiferromagnetically at Tc=52±1 K, slightly below a maximum in χ(T) at T(χmax)=57.2±0.5 K, with χmax=0.0331±0.0003 emu/mol. The ratio Tc/T(χmax)=0.91±0.02 does not suggest lower magnetic dimensionality. Magnetization isotherms are linear to 16 kG; some features suggesting lower temperature transitions occur. Well above Tc the susceptibility is analyzed assuming axial and rhombic crystal field distortions, i.e., D[Sˆz2−S(S+1)/3] and E[Sˆx2−Sˆy2] spin Hamiltonian terms, with exchange incorporated in a mean field approximation. An extraordinarily large ||D/k||≈119 K seems to emerge, a result which is very provisional lacking single crystal data. A mean field analysis of Tc and θ yields ferromagnetic intrachain exchange J1/k=8.6±0.5 K and antiferromagnetic interchain exchange J2/k=−0.76±0.4 K. It seems more likely that D is negative, but even if it is positive the exchange interaction is large enough to induce magnetic order at finite Tc in light of theories relating Tc, J, and D.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.353740
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