Related papers: Simultaneous suppression of ferromagnetism and sup…
Recently, coexistence of ferromagnetism (T_Curie = 2.8K) and superconductivity (T_sc = 0.8K) has been reported in UCoGe, a compound close to a ferromagnetic instability at ambient pressure P. Here we present resistivity measurements under…
UCoGe is one of the few compounds showing the coexistence of ferromagnetism and superconductivity at ambient pressure. With T_Curie = 3 K and T_SC = 0.6 K it is near a quantum phase transition; the pressure needed to suppress the magnetism…
The pressure-temperature phase diagram of the orthorhombic ferromagnetic superconductor UCoGe was determined by resistivity measurements up to $10.5~$GPa. The Curie temperature $T_C$ is suppressed with pressure and vanishes at the critical…
We report a high-pressure single crystal study of the superconducting ferromagnet UCoGe. Ac-susceptibility and resistivity measurements under pressures up to 2.2 GPa show ferromagnetism is smoothly depressed and vanishes at a critical…
We report the coexistence of ferromagnetic order and superconductivity in UCoGe at ambient pressure. Magnetization measurements show that UCoGe is a weak ferromagnet with a Curie temperature T_{C}= 3 K and a small ordered moment $m_{0}$=…
A variety of heavy fermion superconductors, such as UCoGe, UGe$_2$, and URhGe exhibit a striking coexistence of bulk ferromagnetism and superconductivity. In these systems, the magnetic moment decreases with pressure, and vanishes at a…
We have investigated the impact of Ru substitution for Co on the behavior of the ferromagnetic superconductor UCoGe by performing x-ray diffraction, magnetization, specific heat and electrical resistivity measurements on polycrystalline…
UCoGe exhibits superconductivity in the presence of ferromagnetism. When a field is applied along the b axis (perpendicular to the easy axis), ferromagnetism is weakened and superconductivity is enhanced. This enhancement has been…
Unambiguous evidence for the microscopic coexistence of ferromagnetism and superconductivity in UCoGe ($T_{\rm Curie} \sim 2.5$ K and $T_{\rm SC}$ $\sim$ 0.6 K) is reported from $^{59}$Co nuclear quadrupole resonance (NQR). The…
The correlated metal UCoGe is a weak itinerant ferromagnet with a Curie temperature T_C = 3 K and a superconductor with a transition temperature T_s = 0.6 K. We review its basic thermal, magnetic - on the macro and microscopic scale - and…
We review our recent results on ferromagnetic superconductors, URhGe and UCoGe. High quality single crystals of both compounds were successfully grown. The specific heat shows a clear jump related to the superconducting transition in UCoGe.…
The phase separation of the ferromagnetic (FM) and paramagnetic (PM) phases in the superconducting (SC) state of UCoGe at the FM critical region was investigated using $^{59}$Co nuclear quadrupole resonance (NQR) technique by taking…
In the correlated metal URhGe ferromagnetic order (T_C = 9.5 K) and superconductivity (T_s= 0.25 K) coexist at ambient pressure. Here we report on alloying URhGe by Ru, which enables one to tune the Curie temperature to 0 K. URuGe has a…
Thermal conductivity measurements in the superconducting state of the ferromagnet UCoGe were performed at very low temperatures and under magnetic field on samples of different qualities and with the heat current along the three…
We report on a microscopic study of the evolution of ferromagnetism in the Ru substituted ferromagnetic superconductor (FM SC) UCoGe crystallizing in the orthorhombic TiNiSi-type structure. For that purpose, two single crystals with…
The evolution of magnetic properties of isostructural and isoelectronic solid solutions of the superconducting itinerant 5f-electron ferromagnet UCoGe with antiferromagnet UIrGe was studied by magnetization, AC susceptibility, specific…
A $^{59}$Co nuclear quadrupole resonance (NQR) was performed on a single-crystalline ferromagnetic (FM) superconductor UCoGe under pressure. The FM phase vanished at a critical pressure $P_c$, and the NQR spectrum just below $P_c$ showed…
Single-crystals of the new ferromagnetic superconductor UCoGe have been grown. The quality of as-grown samples can be significantly improved by a heat-treatment procedure, which increases the residual resistance ratio (RRR) from ~5 to ~30.…
We present high field magnetoresistance, Hall effect and thermopower measurements in the Ising-type ferromagnetic superconductor UCoGe. Magnetic field is applied along the easy magnetization $c$ axis of the orthorhombic crystal. In the…
We review our recent studies on ferromagnetic superconductors, UGe2, URhGe and UCoGe, together with the ferromagnetic quantum criticality and paramagnetic singularity on the Ising 5f-itinerant system UCoAl. Thanks to the variety of ordered…