title: Characteristic crossing point (T(*)≈2.7 K) in specific heat curves of samples RuSr(2)Gd(1.5)Ce(0.5)Cu(2)O(10-δ) taken for different values of magnetic field.
abstract: Magnetic properties of polycrystalline samples of RuSr(2)(Gd(1.5)Ce(0.5))Cu(2)O(10-δ), as-prepared (by solid-state reaction) and annealed (12 h at 845 °C) in pure oxygen at different pressure (30, 62 and 78 atm) are presented. The specific heat and magnetization were investigated in the temperature range 1.8-300 K with a magnetic field up to 8 T. The specific heat, C(T), shows a jump at the superconducting transition (with an onset at T≈37.5 K). Below 20 K, a Schottky-type anomaly becomes apparent in C(T). This low-temperature anomaly can be attributed to splitting of the ground term (8)S(7/2) of paramagnetic Gd(3+) ions by internal and external magnetic fields. It is found that curves C(T) taken for different values of magnetic field have the same crossing point (at T(*)≈2.7 K) for all the samples studied. At the same time, C(H) curves taken for different temperatures have a crossing point at a characteristic field H(*)≈3.7 T. These effects can be considered as a manifestation of the crossing point phenomenon which is supposed to be inherent for strongly correlated electron systems.
authors.affiliation: B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences, Kharkov, 61103, Ukraine.
authors.forename: B I
authors.initials: BI
authors.lastname: Belevtsev
authors.forename: V B
authors.initials: VB
authors.lastname: Krasovitsky
authors.forename: D G
authors.initials: DG
authors.lastname: Naugle
authors.forename: K D D
authors.initials: KD
authors.lastname: Rathnayaka
authors.forename: G
authors.initials: G
authors.lastname: Agnolet
authors.forename: I
authors.initials: I
authors.lastname: Felner