An overview of quantum phase transitions (QPTs) in metallic ferromagnets, discussing both
experimental and theoretical aspects, is given. These QPTs can be classified with respect to …

The discovery of a new superconductor, LaFeAsO1− xFx with a superconducting critical
temperatureT, c, of 26 K in 2008, has quickly renewed interest in the exploration of iron …

Two major themes in the physics of condensed matter are quantum critical phenomena and
unconventional superconductivity. These usually occur in the context of competing …

We report zero-field muon spin relaxation (μ SR) measurements on R FeAsO with R= La,
Ce, Pr, and Sm. We study the interaction of the FeAs and R (rare-earth) electronic systems in …

Superconductivity in the iron pnictides and chalcogenides arises at the border of
antiferromagnetism, which raises the question of the role of quantum criticality. In this topical …

We present results of transport and magnetic properties and heat capacity measurements on
polycrystalline CeFeAsO, PrFeAsO and NdFeAsO. These materials undergo structural …

The electronic structure in the normal state of CeFeAsO 0.89 F 0.11 oxypnictide
superconductors has been investigated with x-ray absorption and photoemission …

We present a new Kondo-lattice system, YbNi 4 P 2, which is a clean heavy-fermion metal
with a severely reduced ferromagnetic (FM) ordering temperature at TC= 0.17 K, evidenced …

We present a thorough experimental study of the three-dimensional hyperhoneycomb Kitaev
magnet β-Li 2 IrO 3, using a combination of inelastic neutron scattering (INS), time-domain …

Abstract We study the spin-1/2 J 1− J 2 Heisenberg model on a square lattice using the
cluster mean-field theory. We find a rapid convergence of phase boundaries with increasing …