451 research outputs found
Uniaxial stress tuning of geometrical frustration in a Kondo lattice
Hexagonal CeRhSn with paramagnetic moments on a distorted Kagome lattice
displays zero-field quantum critical behavior related to geometrical
frustration. We report high-resolution thermal expansion and magnetostriction
measurements under multiextreme conditions such as uniaxial stress up to 200
MPa, temperatures down to 0.1 K and magnetic fields up to 10 T. Under uniaxial
stress along the -direction, quantum criticality disappears and a complex
magnetic phase diagram arises with a sequence of phases below 1.2 K and fields
between 0 and 3 T (). Since the Kondo coupling increases with
stress, which alone would stabilize paramagnetic behavior in CeRhSn, the
observed order arises from the release of geometrical frustration by in-plane
stress.Comment: Accepted in PRB Rapid Com
Resistivity, Hall effect and Shubnikov-de Haas oscillations in CeNiSn
The resistivity and Hall effect in CeNiSn are measured at temperatures down
to 35 mK and in magnetic fields up to 20 T with the current applied along the
{\it b} axis. The resistivity at zero field exhibits quadratic temperature
dependence below 0.16 K with a huge coefficient of the term (54
cm/K). The resistivity as a function of field shows an
anomalous maximum and dip, the positions of which vary with field directions.
Shubnikov-de Haas (SdH) oscillations with a frequency {\it F} of 100 T
are observed for a wide range of field directions in the {\it ac} and {\it bc}
planes, and the quasiparticle mass is determined to be 10-20 {\it m}.
The carrier density is estimated to be electron/Ce. In a narrow
range of field directions in the {\it ac} plane, where the
magnetoresistance-dip anomaly manifests itself clearer than in other field
directions, a higher-frequency () SdH oscillation is
found at high fields above the anomaly. This observation is discussed in terms
of possible field-induced changes in the electronic structure.Comment: 15 pages, 5 figures, to appear in Phys. Rev. B (15 Sept. 2002 issue
Direct observation of Fe spin reorientation in single crystalline YbFe6Ge6
We have grown single crystals of YbFe6Ge6 and LuFe6Ge6 and characterized
their anisotropic behaviour through low field magnetic susceptibility,
field-dependent magnetization, resistivity and heat capacity measurements. The
Yb+3 valency is confirmed by LIII XANES measurements. YbFe6Ge6 crystals exhibit
a field-dependent, sudden reorientation of the Fe spins at about 63 K, a unique
effect in the RFe6Ge6 family (R = rare earths) where the Fe ions order
anti-ferromagnetically with Neel temperatures above 450 K and the R ions'
magnetism appears to behave independently. The possible origins of this unusual
behaviour of the ordered Fe moments in this compound are discussed.Comment: 12 pages, 8 figures, accepted in J. Phys.: Cond. Matte
Online Self-Indexed Grammar Compression
Although several grammar-based self-indexes have been proposed thus far,
their applicability is limited to offline settings where whole input texts are
prepared, thus requiring to rebuild index structures for given additional
inputs, which is often the case in the big data era. In this paper, we present
the first online self-indexed grammar compression named OESP-index that can
gradually build the index structure by reading input characters one-by-one.
Such a property is another advantage which enables saving a working space for
construction, because we do not need to store input texts in memory. We
experimentally test OESP-index on the ability to build index structures and
search query texts, and we show OESP-index's efficiency, especially
space-efficiency for building index structures.Comment: To appear in the Proceedings of the 22nd edition of the International
Symposium on String Processing and Information Retrieval (SPIRE2015
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