Spin anisotropy in Cu(en)(H2O)2SO

Influence of Pressure on the Magnetic Response of the Low-Dimensional Quantum Magnet Cu(H2O)2(C2H8N2)SO4

“…3. The ambient pressure data are in agreement with previous studies [1,2], and when using the piston cell, the temperature dependences of the magnetic responses under pressure are identical, except for a vertical shift coming from a change in the background that was not subtracted for clarity. Since no changes were detected up to 0.6 GPa, a decision was made not to continue to higher pressures in the piston cell, but to shift the experiments to the anvil cell.…”

“…The synthesis and structural characterizations of the large crystals Cu(H 2 O) 2 (C 2 H 8 N 2 )SO 4 are described elsewhere [2]. For each run, small pieces or flakes from the large parent crystals were used.…”

“…For example, experimental studies identified Cu(H 2 O) 2 (en)SO 4 (en = ethylenediamine = C 2 H 8 N 2 ) as a quasi-two-dimensional S = 1/2 spatially-anisotropic triangular-lattice antiferromagnet, Fig. 1 [1,2]. On the other hand, a theoretical ab initio investigation of the exchange interactions between Cu ions indicated the system is a quasi-one dimensional magnet [3,4], with the exchange coupling between the Cu atoms being propagated along a zig-zag line in the b-c plane and connecting the Cu atoms through the N atoms, Fig.…”

“…The data suggest a possible a shift in the magnetization peak of the material at the lowest temperatures and at the highest applied pressures. * corresponding author; e-mail: meisel@phys.ufl.edu The previous experimental studies interpreted the magnetic response in terms of a two-dimensional triangularlattice with interaction parameters J1 and J2 in the a-b plane [1,2]. (c) The theoretical ab initio work used six, magnetic exchange parameters and found J4, in the b-c plane, to be the largest by a factor of about 7 compared to the next largest exchange, J6, at P = 0, resulting in an one-dimensional zig-zag chain system [3,4].…”

Interplay of Spin and Spatial Anisotropy in Low-Dimensional Quantum Magnets with Spin 1/2

“…Considering dx 2 -y 2 ground state of the Cu(II) ion, it was assumed that potential exchange pathways form SATL with a dominant exchange coupling creating the square lattice, while weaker interactions were expected to occur along one of the diagonals of the square plaquettes [65]. The analysis of single-crystal electron paramagnetic resonance spectra [80] indicated the need to revisit the concept of SATL in Cu(en)(H2O)2SO4, which triggered first-principle calculations of exchange couplings [81]. The calculations revealed the formation of a spatially anisotropic zig-zag square lattice ( Figure 7a Such calculations proved to be very important in the identification of the 2D quantum magnet Cu(en)(H 2 O) 2 SO 4 .…”