S=½ Ising Behavior in the Two-dimensional Molecular Magnet Fe(NCS)2(pyrazine)2
- Hahn-Meitner Institut, Berlin, Germany
- ISIS Facility, Rutherford Appleton Laboratory
- ORNL
- University of Montpellier, France
- Northeastern University
The magnetic ordering and critical behavior of antiferromagnetic Fe(NCS){sub 2}(pyrazine){sub 2} has been studied by neutron powder diffraction (NPD), inelastic neutron scattering (INS), Moessbauer spectroscopy, and magnetic measurements. The system can be regarded as a two-dimensional (2D) antiferromagnet even in the ordered phase, given that long-range magnetic ordering between the layers simply follows a necessary consequence of the establishment of long-range ordering within the planes. The INS data, which were taken on a cold neutron time-of-flight spectrometer, reveals that when the temperature is lowered towards T{sub N}, the correlation length within the 2D layers increases and ultimately crosses over from two- to three-dimensional (3D) behavior. Indeed, 3D long-range antiferromagnetic order, associated with a propagation vector [1,0,1/4+{epsilon}], is observed in the NPD data below 6.8 K. Furthermore, in agreement with the behavior of both {chi}(T) and C{sub m}(T) data, the order parameter follows the exact Osanger solution for a 2D S = 1/2, Ising system.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1003367
- Journal Information:
- Physical Review B, Vol. 69, Issue 22; ISSN 1098--0121
- Country of Publication:
- United States
- Language:
- English
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