[en] The authors report specific heat measurements in a broad temperature range between 0.06 and 20 K on single crystalline CeRu₂Si₂ in magnetic fields applied parallel to the c-direction around the critical field B_M, where the metamagnetic transition from the itinerant to the localized state takes place. In the critical field B_M parallel c = 7.8 T a distinct deviation from the usual Fermi-liquid behavior is found down to the lowest temperature. below 1.8 K C/T varies as (1minusaT), while for 1.8K < T < 20 K a power law T^λ-1 with λ = 0.66 is found. Small deviations from the critical magnetic field leads to the recovery of a Fermi-liquid ground state. The observed behavior of the specific heat at the field induced magnetic instability is discussed in the context of a non-Fermi-liquid state and compared with those for the field-induced nFl CeCu_6-xAg_x and the recent observation of nFl behavior at B_M in UPt₃

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[en] Due to their outstanding properties, e.g., good contrast, wide viewing angle, low power consumption, and self-emission organic light-emitting (OLE) displays on the basis of conjugated polymers are on the verge of commercialization. Two major disadvantages of the current processing technique for the polymersemdashspin coatingemdashare the material waste and the difficulties involved in patterning multichrome or even full-color displays. Therefore, we investigated the screen-printing technique for the production of OLE displays. In this letter, we present performance data and images of screen-printed OLE diodes. They are already comparable to spin-coated ones. We observed luminance of 10000 cd/m2 at 8 V and peak efficiencies exceeding 10 cd/A for green diodes. These data indicate that printed organic displays have the potential to replace 'classical' spin-coated devices. [copyright] 2001 American Institute of Physics

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[en] We present a reinvestigation of the complex magnetic phase diagram of the heavy-fermion system Ce(Cu_1-xNi_x)₂Ge₂ by employing measurements of the specific heat, C(T), and thermal expansion, x(T), on high-quality single crystals with X = 0, 0.02, 0.05, 0.5 and 0.8 in magnetic fields B ≤ 8T. In addition to what was observed in polycrystalline samples multiple phase-transition anomalies could be resolved in these single crystals for x < 0.5 and 1.5 K < T < T_N. Sharp anomalies in C(T) and thermal hysteresis in x(T) give evidence that these transitions are of first order (x = 0.02, 0.05). Our findings demonstrate that the structure of the antiferromagnetically ordered state depends on subtle changes of the hybridization of the Ce-4f state to its local environment, while the interplay of Kondo- and RKKY-interaction, which determines the existence of a long-range ordered state is governed by volume and or density-of-states effects. (orig.)