Magnetic Properties of Synthetic Libethenite Cu₂PO₄OH:  a New Spin-Gap System

Abstract

Synthetic mineral libethenite Cu(2)PO(4)OH was prepared by the hydrothermal method, and its structure at 200 K was refined by single-crystal X-ray diffraction. The structure of Cu(2)PO(4)OH is built up from Cu2(2)O(6)(OH)2 dimers of edge-sharing Cu2O(4)(OH) trigonal bipyramids and [Cu1(2)O(6)(OH)(2)] proportional chains of edge-sharing Cu1O(4)(OH)(2) octahedra. Magnetic properties of Cu(2)PO(4)OH were investigated by magnetic susceptibility, magnetization, and specific heat measurements. Cu(2)PO(4)OH is a spin-gap system with a spin gap of about 139 K. It was shown by spin dimer analysis that, to a first approximation, the magnetic structure of Cu(2)PO(4)OH is described by an isolated square-spin cluster model defined by the Cu1-O-Cu2 superexchange J with Cu1...Cu2 = 3.429 A. The fitting analysis of the magnetic susceptibility data with a square-spin cluster model results in J/k(B) = 138 K. Specific heat data show that Cu(2)PO(4)OH does not undergo a long-range magnetic ordering down to 1.8 K. We also report vibrational properties studied with Raman spectroscopy and the thermal stability of Cu(2)PO(4)OH.

Control of entanglement transitions in quantum spin clusters

“…The effect is smoothed by temperature, but it is clearly visible for T ∼ 5% of J . Two sample values of J /k B for real cluster magnets are 17 K for Cr 8 [26] and 138 K for Cu 2 PO 4 OH [23]. A smaller peak is seen also at the field at which there is another level crossing.…”

Magnetic excitations in anS=12diamond-shaped tetramer compoundCu2PO4OH

“…11. The inelastic neutron scattering experiments were carried out on a chopper neutron spectrometer ARCS, 14 installed at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL).…”

“…Cu 2 PO 4 OH is a candidate material for the S=1/2 diamond-shaped antiferromagnetic tetramer system, 11 as shown in Fig. 1.…”

Analysis of Spin Exchange Interactions in (C2N2H10)[Fe(HPO3)F3] on the Basis of Electronic Structure Calculations

“…2 > values obtained from EHTB calculations, [3][4][5][6][7] when both the d orbitals of the transition metal ions and the s/p orbitals of its surrounding ligands are represented by double-zeta Slater type orbitals (DZ-STO's). Our calculations are carried out using the atomic parameters summarized in the Table 1.…”

“…structural units containing two spin sites). [3][4][5][6][7] The strength of SSE interaction of a spin dimer increases with increasing the overlap between the magnetic orbital (i.e. singly occupied molecular orbital containing unpaired spin) of a given spin dimer.…”