CeRhIn5 has an unusual transition at a critical pressure of ∼15 kbar. Specificheat data show a gradual change in the zero-field 'magnetic' anomaly from one typical of antiferromagnetic (AF) ordering at ambient pressure to one that is more characteristic of a Kondo-singlet ground state at 21 kbar. However, at 15 kbar there is a discontinuous change from an AF ground state to a superconducting ground state, with evidence of a weak thermodynamic first-order transition. For pressures near 12 kbar, there is a pressure-dependent, second-order transition. The low-energy excitations above 15 kbar are characteristic of superconductivity with line nodes in the energy gap, and with extended gapless behaviour at intermediate pressures less than 21 kbar.

CeRhIn5 is known to show an unusual transition at a critical pressure of ∼15 kbar. Specific-heat data show a gradual change in the zero-field "magnetic" specific-heat anomaly from one typical of antiferromagnetic ordering at ambient pressure to one more characteristic of a Kondo singlet ground state at 21 kbar. However, at 15 kbar there is a discontinuous change from an antiferromagnetic ground state to a superconducting ground state, and evidence of a weak thermodynamic first-order transition. Above the critical pressure, the low-energy excitations are characteristic of superconductivity with line nodes in the energy gap, and, at intermediate pressures, of extended gaplessness. © 2002 Plenum Publishing Corporation.

CeRhIn5 is known to show an unusual transition at a critical pressure of ∼15 kbar. Specific-heat data show a gradual change in the zero-field "magnetic" specific-heat anomaly from one typical of antiferromagnetic (AF) ordering at ambient pressure to one more characteristic of a Kondo singlet ground state at 21 kbar. However, at 15 kbar there is a discontinuous change from an AF ground state to a superconducting ground state, and evidence of a weak thermodynamic first-order transition. Above the critical pressure, the low-energy excitations are characteristic of superconductivity with line nodes in the energy gap, and, at intermediate pressures, of extended gaplessness. © 2003 Elsevier Science B.V. All rights reserved.

We report a new family of Ce-based heavy-fermion compounds whose electronic specific heat coefficients range from about 400 to over 700mJ/mol-Ce K2. Crystals in this family form as CenTmIn3n-2m, where T = Rh or Ir, n = 1 or 2, and m = 1, with a tetragonal structure that can be viewed as m-layers of CeIn3 units stacked sequentially along the c-axis with intervening m-layers of TIn2. Ambient and high-pressure studies show that the quasi-2D layers of CeIn3 produce unconventional superconducting and magnetic ground states. This family should enable new understanding of the relationship between magnetism and superconductivity in heavy-fermion materials and more generally of why heavyfermion superconductivity prefers to develop in one structure type and not another. © 2001 Elsevier Science B.V. All rights reserved.