R. Helfrich

High-resolution ac-calorimetry studies of the quasi-two- dimensional organic superconductor kappa-(BEDT- TTF)2Cu(NCS)2

We report high-resolution specific-heat measurements on the quasi-two-dimensional organic superconductor

New observations concerning magnetism and superconductivity in heavy-fermion metals

\ensuremath{\kappa}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}\mathrm{Cu}(\mathrm{NCS}{)}_{2},

New observations concerning the low-temperature properties of the carrier-poor heavy-fermion system Yb4As3

performed by using a sensitive ac-modulation technique. The main observations are (i) a discontinuity at

Strongly correlated electron system without free carrier Yb4(As1-xPx)3

{T}_{c}

Systematic study in mixed valence system Yb4(As1−xSbx)3

much in excess of what is expected for a weak-coupling BCS superconductor and (ii) a quasiparticle contribution to the specific heat with an exponentially weak temperature dependence at

Doping effects on UPd2Al3

T\ensuremath{\ll}{T}_{c}.

Non-Fermi liquid normal state of the heavy-fermion superconductor UBe13

The latter finding is incompatible with an order parameter that vanishes at certain parts of the Fermi surface. The data for

Evidence for the existence of two variants of UBe13

Tl~{T}_{c}

“Non-Fermi-liquid” phenomena in heavy-fermion CeCu2Si2 and CeNi2Ge2

can be well described by a strong-coupling extension of the BCS theory \char22{} the

New results on the low-T phase diagram of U1-xThxBe13: A thermodynamic study

\ensuremath{\alpha}