5 research outputs found
Ferromagnetic bubble clusters in YCaMnO thin films
We studied the ferromagnetic topology in a YCaMnO thin
film with a combination of magnetic force microscopy and magnetization
measurements. Our results show that the spin-glass like behavior, reported
previously for this system, could be attributed to frustrated interfaces of the
ferromagnetic clusters embedded in a non-ferromagnetic matrix. We found
temperature dependent changes of the magnetic topology at low temperatures,
which suggests a non-static Mn/Mn ratio
New Superconducting and Magnetic Phases Emerge on the Verge of Antiferromagnetism in CeIn
We report the discovery of new superconducting and novel magnetic phases in
CeIn on the verge of antiferromagnetism (AFM) under pressure () through
the In-nuclear quadrupole resonance (NQR) measurements. We have found a
-induced phase separation of AFM and paramagnetism (PM) without any trace
for a quantum phase transition in CeIn. A new type of superconductivity
(SC) was found in GPa to coexist with AFM that is magnetically
separated from PM where the heavy fermion SC takes place. We propose that the
magnetic excitations such as spin-density fluctuations induced by the
first-order magnetic phase transition might mediate attractive interaction to
form Cooper pairs.Comment: 4 pages, 4 EPS figures, submitted to J. Phys. Soc. Jp
Evolution of an Unconventional Superconducting State inside the Antiferromagnetic Phase of CeNiGe under Pressure: a Ge-Nuclear-Quadrupole-Resonance Study
We report a Ge nuclear-quadrupole-resonance (NQR) study on novel
evolution of unconventional superconductivity in antiferromagnetic (AFM)
CeNiGe. The measurements of the Ge-NQR spectrum and the nuclear
spin-lattice relaxation rate () have revealed that the unconventional
superconductivity evolves inside a commensurate AFM phase around the pressure
() where N\'{e}el temperature exhibits its maximum at 8.5 K. The
superconducting transition temperature has been found to be
enhanced with increasing , before reaching the quantum critical
point at which the AFM order collapses. Above , the AFM structure
transits from an incommensurate spin-density-wave order to a commensurate AFM
order at K, accompanied by a longitudinal spin-density fluctuation.
With regard to heavy-fermion compounds, these novel phenomena have hitherto
never been reported in the - phase diagram.Comment: 4 pages, 5 figure
Unconventional Superconductivity in Heavy Fermion Systems
We review the studies on the emergent phases of superconductvity and
magnetism in the -electron derived heavy-fermion (HF) systems by means of
the nuclear-quadrupole-resonance (NQR) under pressure. These studies have
unraveled a rich variety of the phenomena in the ground state of HF systems. In
this article, we highlight the novel phase diagrams of magnetism and
unconventional superconductivity (SC) in CeCuSi, HF antiferromagnets
CeRhIn, and CeIn. A new light is shed on the difference and common
features on the interplay between magnetism and SC on the magnetic criticality.Comment: 15 pages, 13 figures, to appear in J. Phys. Soc. JPN, 74, No.1
(2005), special issue "Kondo Effect- 40 Years after the Discovery