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We measured specific heat and resistivity of heavy fermion CeCoIn5 at and above the superconducting critical field with field in [001] (Hc2 = 5 T) and [100] directions (Hc2, = 12 T), and at temperatures down to 50 mK. At the critical fields the data show Non Fermi Liquid (NFL) behavior down to the lowest temperatures. With increasing field the data exhibit crossover from NFL to Fermi liquid behavior at the lowest temperatures. Analysis of the scaling properties of the specific heat, and comparison of both resistivity and the specific heat with the predictions of a spin‐fluctuation theory suggest that the NFL behavior is due to incipient antiferromagnetism (AF) in CeCoIn5 with the quantum critical point in the vicinity of Hc2 Below Hc2 the AF phase which competes with the paramagnetic ground state is superseded by the superconducting transition. To separate the quantum critical point HQCP from the superconducting critical field Hc2 we performed a series of Sn‐doping and hydrostatic pressure studies. Sn‐dop...

We describe the design and operation of a cryogenic magnetic resonance force microscope suitable for detecting electron spin and ferromagnetic resonance. Microscope‐critical components are described, including scanning probe stages, cantilever with a micromagnet attached, fiber optic interferometer, and microwave resonator. The performance of the apparatus has been evaluated at 4 K using diphenylpicrylhydrazyl (DPPH) as a reference sample. Our experiments have demonstrated the sensitivity of the microscope to be better than 3×104 electron spins.

We report transverse magnetoresistance in a CeIrIn5 single crystal at magnetic fields up to 33T and temperatures down to 25mK, with the magnetic field oriented along the c‐axis of this tetragonal heavy fermion compound. The metamagnetic transition is marked by a characteristic drop in resistivity at the lowest temperatures as the magnetic field is increased. Resistivity shows Non‐Fermi Liquid behavior above and below the metamagnetic transition field. These results are suggestive of a field‐tuned metamagnetic quantum critical point in CeIrIn5.

We have conducted an ultrasonic pulse‐time‐of‐flight investigation of the squashing mode of the superfluid 3He‐B in a magnetic field. All five of the expected Zeeman sublevels for this J=2− mode were observed. The investigation was done at very low temperature (T/Tc