Synthesis of the new oxocuprate Cu5Bi2B4O14 and investigation of its structural, magnetic, and resonant properties

Single crystals of the new compound Cu₅Bi₂B₄O₁₄ are grown and its structural, magnetic, and resonant properties are investigated for the first time. It is found that the Cu₅Bi₂B₄O₁₄ crystal synthesized has a triclinic symmetry with space group $P\bar 1$ and the unit cell parameters a=10.132 Å, b=9.385 Å, c=3.458 Å, α=105.443°, β=97.405°, γ=107.784°, and Z=1. At a temperature of 24.5 K, the crystal undergoes a magnetic phase transition to the magnetically ordered state. The assumption is made that the ferrimagnetic structure of the Cu₅Bi₂B₄O₁₄ crystal consists of two ferromagnetic sublattices coupled through the antiferromagnetic exchange interaction. The unit cell of the crystal contains five copper ions, of which one ion belongs to the first sublattice and the other four ions form the second sublattice. Analysis of the resonant and magnetic static properties demonstrates that the Cu₅Bi₂B₄O₁₄ crystal exhibits an easy-axis magnetic anisotropy. The direction of the easy axis coincides with the c axis of the crystal, whereas the a and b axes are the hard magnetic axes with saturation fields approximately equal to 25 and 10 kOe, respectively.