Magnetic phase transitions in RCu2Ge2 (R = Dy − Tm) intermetallics

Magnetic and related properties of RCu2Ge2 (R = Dy − Tm) intermetallics were investigated by means of magnetic susceptibility, electrical resistivity and specific heat measurements. The compounds were found to order antiferromagnetically at 6.2 K (DyCu2Ge2), 5.6 K (HoCu2Ge2), 3.0 K (ErCu2Ge2) and 3.9 K (TmCu2Ge2). Electrical transport and heat capacity data were analysed by means of appropriate models giving the Debye and Einstein temperatures estimation. By extracting purely magnetic contribution to the heat capacity the Schottky effect due to crystalline electric field (CF) was evidenced. The corresponding CF levels schemes were estimated, as well. Moreover, the magnetic entropy has been calculated for all investigated samples.

Magnetic specific heat of DyCu2Ge2 (a); HoCu2Ge2 (b); ErCu2Ge2 (c) and TmCu2Ge2 (d). Solid lines denote Schottky contribution originating from crystal field levels scheme as presented in insets. In the insets to the part (a) and (c) all levels are doublets. In rest cases, there are doublets (thick bars) or singlets (thin bars) shown.Figure optionsDownload as PowerPoint slideHighlights
► DyCu2Ge2, HoCu2Ge2, ErCu2Ge2, TmCu2Ge2 are antiferromagnets with ordering temperatures of 6.2 K 5.6 K, 3.0 K and 3.9 K, respectively.
► Magnetic ordering for TmCu2Ge2 was reported for the first time.
► Crystal electric field splitting scheme was derived from calorimetric studies.
► The characteristic Debye temperatures were estimated on basis of resistivity and calorimetric studies.