B I Belevtsev et al 2009 J. Phys.: Condens. Matter 21 455602 doi:10.1088/0953-8984/21/45/455602
B I Belevtsev1,4, V B Krasovitsky1, D G Naugle2, K D D Rathnayaka2, G Agnolet2 and I Felner3
Show affiliationsMagnetic properties of polycrystalline samples of RuSr2(Gd1.5Ce0.5)Cu2O10−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 8S7/2 of paramagnetic Gd3+ 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.
74.25.Bt Thermodynamic properties
74.72.Jt Other cuprates, including Tl and Hg-based cuprates
71.27.+a Strongly correlated electron systems; heavy fermions
Issue 45 (11 November 2009)
Received 22 August 2009, in final form 3 October 2009
Published 23 October 2009
B I Belevtsev et al 2009 J. Phys.: Condens. Matter 21 455602
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