R.J. Keizer

Magnetism in heavy-fermion U(Pt,Pd)3 studied by µSR

We report µSR experiments carried out on a series of heavy-electron pseudobinary compounds U(Pt1-xPdx)3 (x0.05). For x0.005 the zero-field muon depolarization is described by the Kubo-Toyabe function. However the temperature variation of the Kubo-Toyabe relaxation rate KT(T) does not show any sign of the small-moment antiferromagnetic phase with TN6 K (signalled by neutron diffraction), in contrast to previous reports. The failure to detect the small ordered moment suggests it has a fluctuating (>10 MHz) nature, which is consistent with the interpretation of NMR data. For 0.01 x0.05 the muon depolarization in the ordered state is described by two terms of equal amplitude: an exponentially damped spontaneous oscillation and a Lorentzian Kubo-Toyabe function. These terms are associated with antiferromagnetic order with substantial moments. The Knight shift measured in a magnetic field of 0.6 T on single-crystalline U(Pt0.95Pd0.05)3 in the paramagnetic state shows two signals for Bc, while only one signal is observed for Bc. The observation of two signals for Bc, while there is only one muon localization site (0,0,0), points to the presence of two spatially distinct regions of different magnetic response.

Neutron-diffraction study of the evolution of antiferromagnetic order in UPt3 doped with Pd

Neutron-diffraction experiments have been carried out on U(Pt1-xPdx)3 single crystals (x = 0.01 a large moment antiferromagnetic phase (LMAF) is found. For this phase at optimum doping (x= 0.05) TN attains a maximum value of 5.8 K and the ordered moment equals 0.63(5) mB/U-atom. TN(x) for the LMAF follows a Doniach-type phase diagram. We infer that the antiferromagnetic instability in U(Pt1-xPdx)3 is located in the range 0.5-1 at.% Pd.

Evidence for a Two Component Magnetic Response in UPt3

The magnetic response of the heavy fermion superconductor UPt3 has been investigated on a microscopic scale by muon Knight shift studies. Two distinct and isotropic Knight shifts have been found for the field in the basal plane. While the volume fractions associated with the two Knight shifts are approximately equal at low and high temperatures, they show a dramatic and opposite temperature dependence around T(N). Our results are independent on the precise muon localization site. We conclude that UPt3 is characterized by a two component magnetic response.

Superconductivity in heavy-fermion U(Pt,Pd)3 and its interplay with magnetism

The effect of Pd doping on the superconducting phase diagram of the unconventional superconductor

Suppression of superconductivity in single crystals of UPt3 by Pd substitution

{\mathrm{UPt}}_{3}

μSR study of antiferromagnetic order in UPt3 alloyed with Pd

has been measured by (magneto)resistance, specific heat, thermal expansion, and magnetostriction. Experiments on single- and polycrystalline

μSR study of magnetism in heavy-fermion U(Pt,Pd)3

{\mathrm{U}(\mathrm{P}\mathrm{t}}_{1\ensuremath{-}x}{\mathrm{Pd}}_{x}{)}_{3}

Search for a quantum phase transition in U(Pt1−xPdx)3

for

Studies of superconductivity in U(Pt1-xPdx)3 for x<0.006

xl~0.006

On the interplay of small-moment magnetism and superconductivity in UPt3

show that the superconducting transition temperatures of the A phase