Spin-Glass Behavior in LaCu4Mn Compound

The experimental results of the X-ray powder diffraction, magnetic susceptibility, electrical resistivity, and specific heat measurements of the LaCu₄Mn compound are presented. LaCu₄Mn is an intermetallic compound that crystallizes in the hexagonal CaCu₅-type structure (space group P6/mmm, No. 191), where the atoms on the 3g (1/2, 0, 1/2) site create a kagome lattice, which can cause the spin frustration and leads to a variety of interesting states of matter, such as spin-ice, spin-liquid, and spin-glass states. The Rietveld refinement reveals a random distribution of Mn and Cu atoms on the 3g and 2c site, where about 80% of Mn atoms occupy the 3g site. The lattice parameters are a=5.252(1) Å and c=4.176(1) Å. The low-field zero-field-cooled and field-cooled DC magnetic susceptibilities show splitting below the spin freezing temperature T_f ≈33 K. At 2 K the magnetization M(H) exhibits hysteresis with coercivity field of ≈5 kOe. The AC susceptibility measurements exhibit a frequency-dependent cusp, associated with a frequency-dependent freezing temperature. Moreover, there is no clear sign of long range magnetic order in specific heat and resistivity measurements.