W. Higemoto

Possible Anisotropic Order Parameter in Pyrochlore Superconductor KOs2O6 Probed by Muon Spin Rotation

Magnetic penetration depth (λ eff ) in a pyrochlore superconductor KOs 2 O 6 was studied by means of muon spin rotation (µSR). The temperature dependence of the transverse spin relaxation rate, which is proportional to λ eff -2 , exhibits a considerable deviation from that expected for the empirical two-fluid model (∝ T 4 ), obeying a T 2 tendency. Furthermore, λ eff apparently increases with increasing applied field, suggesting the presence of nonlinear and nonlocal effects. The present result strongly suggests that the superconducting order parameter in KOs 2 O 6 is anisotropic or multigapped with a small energy gap.

Field-Induced Uniform Antiferromagnetic Order Associated with Superconductivity in Pr1-xLaCexCuO4-δ

A strong correlation between field-induced antiferromagnetic (AF) order and superconductivity is demonstrated for an electron-doped cuprate superconductor, Pr 1- x LaCe x CuO 4-δ (PLCCO). In additi...

Possible weak magnetism in MB6 (M:Ca, Ba) probed by muon spin relaxation and muon level-crossing resonance

Abstract The temperature dependence of muon spin relaxation rate exhibits a significant increase below ~130 K in CaB6 and ~110 K in BaB6, while no sigh of spontaneous muon precession signal under a zero field is observed. Moreover, the electric field gradient at the boron site measured by muon level-crossing resonance (µLCR) exhibits a step like change at ~110 K in CaB6. These results suggest a change in electronic state and the associated emergence of weak random magnetism below 110–130 K in these alkaline earth hexaborides.

Magnetic Freezing Transition of the Frustrated Antiferromagnet LiCrTiO4 with Spinel Structure

We report magnetic susceptibility, zero field (ZF) and longitudinal field (LF) muon spin relaxation (μSR) measurements on LiCrTiO4, which is a frustrated antiferromagnet with a spinel type crystal structure. The spin freezing transition is found to occur at 2.7 K in a field of 30 Oe. A fast relaxation in ZF‐μSR develops at around the spin freezing temperature. Spin fluctuations persist even below the spin freezing temperature.