154 research outputs found
Large magnetoresistance anomalies in Dy7Rh3
The compound Dy7Rh3 ordering antiferromagnetically below (TN=) 59 K has been
known to exhibit a temperature (T) dependent electrical resistivity (rho)
behavior in the paramagnetic state unusual for intermetallic compounds in the
sense that there is a broad peak in rho(T) in the paramagnetic state (around
130 K) as though there is a semi-conductor to metal transition. In addition,
there is an upturn below T_N due to magnetic super-zone gap effects. Here we
report the influence of external magnetic field (H) on the rho(T) behavior of
this compound below 300 K. The rise of rho(T) found below TN could be
suppressed at very high fields (>> 60 kOe), thus resulting in a very large
magnetoresistance (MR) in the magnetically ordered state. The most notable
finding is that the magnitude of MR is large for moderate applications of H
(say 80 kOe) in a temperature range far above T_N as well, which is untypical
of intermetallic compounds. Thus, this compound is characterized by large MR
anomalies in the entire T range of investigation.Comment: IOP Selec
Magnetized Plasma Sheath in the Presence of Negative Ions
The sheath formation in a weakly magnetized collisionless electronegative
plasma consisting of electrons, negative and positive ions has been numerically
investigated using the hydrodynamic equations. The electrons and negative ions
are assumed to follow Boltzmann relation. A sheath formation criterion has been
analytically derived. The paper focuses on studying the sheath structure by
varying the electronegativity. It has been observed that the presence of
negative ions has a substantial effect on the sheath structure. The
observations made in the present work have profound significance on processing
plasmas, especially in the semiconductor industry as well as in fusion studies
A contribution to the life-history of Sphenoclea Zeylanica gaertn
This article does not have an abstract
Study of two-electron temperature plasma sheath using non-extensive electron distribution in presence of an external magnetic field
publishedVersio
Long range magnetic ordering in a spin-chain compound, CaCuMnO, with multiple bond distances
The results of ac and dc magnetization and heat capacity measurements as a
function of temperature (T = 1.8 to 300 K) are reported for a
quasi-one-dimensional compound, CaCuMnO, crystallizing in a
triclinically distorted KCdCl-type structure. The results reveal that
this compound undergoes antiferromagnetic ordering close to 5.5 K. In addition,
there is another magnetic transition below 3.6 K. Existence of two long-range
magnetic transitions is uncommon among quasi-one-dimensional systems. It is
interesting to note that both the magnetic transitions are of long-range type,
instead of spin-glass type, in spite of the fact that the Cu-O and Mn-O bond
distances are multiplied due to this crystallographic distortion. In view of
this, this compound could serve as a nice example for studying
"order-in-disorder" phenomena.Comment: Physical Review (in press
Enhanced electrical resistivity before N\'eel order in the metals, RCuAs (R= Sm, Gd, Tb and Dy
We report an unusual temperature (T) dependent electrical resistivity()
behavior in a class of ternary intermetallic compounds of the type RCuAs
(R= Rare-earths). For some rare-earths (Sm, Gd, Tb and Dy) with negligible
4f-hybridization, there is a pronounced minimum in (T) far above
respective N\'eel temperatures (T). However, for the rare-earths which are
more prone to exhibit such a (T) minimum due to 4f-covalent mixing and
the Kondo effect, this minimum is depressed. These findings, difficult to
explain within the hither-to-known concepts, present an interesting scenario in
magnetism.Comment: Physical Review Letters (accepted for publication
Magnetic frustration in a stoichiometric spin-chain compound, CaCoIrO
The temperature dependent ac and dc magnetization and heat capacity data of
CaCoIrO, a spin-chain compound crystallizing in a KCdCl-derived
rhombohedral structure, show the features due to magnetic ordering of a
frustrated-type below about 30 K, however without exhibiting the signatures of
the so-called "partially disordered antiferromagnetic structure" encountered in
the isostructural compounds, CaCoO and CaCoRhO. This class
of compounds thus provides a variety for probing the consequences of magnetic
frustration due to topological reasons in stoichiometric spin-chain materials,
presumably arising from subtle differences in the interchain and intrachain
magnetic coupling strengths. This compound presents additional interesting
situations in the sense that, ac susceptibility exhibits a large frequency
dependence in the vicinity of 30 K uncharacteristic of conventional
spin-glasses, with this frustrated magnetic state being robust to the
application of external magnetic fields.Comment: Physical Review (Rapid Communications), in pres
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