CuBr2(C10H8N2) - S = 1/2 Two-Dimensional Rectangular Heisenberg Antiferromagnet
E. Čižmár a, M. Kajňakováa, A. Orendáčováa, M. Orendáča, A. Fehera, A.G. Andersb, J.-H. Parkc, d and M.W. Meisel c
aCentre of Low Temperature Physics, P.J. Šafárik University, Park Angelinum 9, SK-04154 Košice, Slovakia
bInstitute for Low Temperature Physics and Engineering, Lenin Av. 47, 310164 Kharkov, Ukraine
cNational High Magnetic Field Laboratory, Tallahassee, FL 32310-3706, USA
dDepartment of Physics and Center for Condensed Matter Sciences, University of Florida, Gainesville FL 32611-8440, USA
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Magnetic susceptibility and X-band electron spin resonance study of a two-dimensional Heisenberg antiferromagnetic system CuBr2(bipy), where bipy = C10H8N2 is 4,4'-bipyridyl, has been performed in the temperature range from 300 K down to 2 K. A rhombic anisotropy of the g-factor was obtained from X-band EPR measurements with gx = 2.037, gy = 2.100 and gz = 2.219. The temperature dependence of the magnetic susceptibility with a round maximum observed at 28 K suggests antiferromagnetic type of short-range order. No signature of the magnetic long-range order in studied compound was observed. The comparison of the magnetic susceptibility data with a two-dimensional rectangular Heisenberg model yields the values of intralayer exchange couplings J/kB = - 47 K and J'/kB = - 9.4 K.
DOI: 10.12693/APhysPolA.118.973
PACS numbers: 75.30.Et, 75.50.Ee, 76.30.-v