317 research outputs found
Evidences for magnetic dimers and skyrmion lattice formation in EuPdSn
Magnetic, thermal and transport properties of the non-centrosymmetric
compound EuPdSn are revisited after including new measurements. In its
paramagnetic phase, the outstanding feature of this compound is the formation
of Eu dimers that allows to understand the deviation of the magnetic
susceptibility from the C-W law below about 70\,K, the field
dependent magnetization variation below \,K and the reduced
entropy at the ordering temperature . A significant change
of the exchange interactions occurs between \,K (where \,K) and \,K (where \,K). The strong electronic
overlap, arising from the reduced Eu-Eu spacing compared with that of pure
Eu is expected to power these quasiparticles formation, inducing a
significant reformulation of the magnetic structure.
A rich magnetic phase diagram is obtained from the analysis of the
derivatives of the magnetic parameters: and
, and the field dependence of the specific heat. Two
critical points are recognized and a tentative description of the magnetic
structures is proposed. The possible formation of a skyrmion lattice, that
arises from the presence of magnetically frustrated pockets in the phase
diagram, is suggested by theoretical studies on hexagonal structures exhibiting
similar interactions pattern.Comment: 13 pages, 11 figure
Searching for a quantum critical point in YbCu5-xAux
Structural, magnetic, transport and thermal properties of YbCu5-xAux alloys
with Au concentration between the limit of structural stability of AuBe5 type
at x = 0.4 up to x = 0.7 are reported. The outstanding features of this system
are: i) the constant and record high values of Cm /T 7J/molK^2 below a
characteristic temperature T*, ranging between 150 mK and 350 mK. ii) A power
law thermal dependence dependence Cm/T(T>T*)=A/T^q, with q = 1.3 +/- 0.1, and
iii) an arising incoherent electronic scattering observed in the resistivity at
T < 1K for x < 0.6 despite the fact that Yb magnetic atoms are placed in a
lattice. Magnetic frustration, originated in the tetrahedral distribution of Yb
atoms, appears as the responsible of the exotic behavior of this system.Comment: 14 pages, 9 figure
Calorimetric tunneling study of heat generation in metal-vacuum-metal tunnel junction
We have proposed novel calorimetric tunneling (CT) experiment allowing exact
determination of heat generation (or heat sinking) in individual tunnel
junction (TJ) electrodes which opens new possibilities in the field of design
and development of experimental techniques for science and technology. Using
such experiment we have studied the process of heat generation in normal-metal
electrodes of the vacuum-barrier tunnel junction (VBTJ). The results show there
exists dependence of the mutual redistribution of the heat on applied bias
voltage and the direction of tunnel current, although the total heat generated
in tunnel process is equal to Joule heat, as expected. Moreover, presented
study indicates generated heat represents the energy of non-equilibrium
quasiparticles coming from inelastic electron processes accompanying the
process of elastic tunneling.Comment: 8 pages, 3 figures, LaTe
Disappearance of Magnetic Transition in (Ce,Gd)Ni5 System
We present the results of an experimental study focused around CeNi5 in the CexGd1??xNi5 system. Pseudobinary bulk samples were prepared with concentration of x = 0:85, 0.9, 0.95, and 0.97 by arc melting method. The structural analysis confirmed the CaCu5 hexagonal crystal structure with P6/mmm space group and proved the existence of a single phase in all of them. The measurement of the magnetic properties shows that the increase of the Ce content leads to lower TC values. Above x = 0:9 spin fluctuations behaviour appears with a shoulder in M(T) around T = 130 K. Heat capacity measurements support these observations.This work was supported by the projects VEGA 2/0032/16, VEGA 1/0956/17, VEGA 1/0611/18, VEGA 1/0053/19, APVV-16-0079 and the Spanish MINECO MAT2017-83631-C3-
YbPd2In : A promising candidate for strong entropy accumulation at very low temperature
We report on synthesis, crystal structure, magnetic, thermodynamic, and transport properties of the compound YbPd2In, crystallizing as a Heusler structure type. A trivalent state of the rare earth was determined by fitting the magnetic susceptibility with a Curie-Weiss law. This compound is characterized by showing very weak magnetic interactions and a negligible Kondo effect. A specific-heat jump was observed at T 48250mK, followed at higher temperature by a power-law decrease of CP(T)/T. The resulting large electronic entropy increase at very low temperature is rapidly shifted to higher temperature by the application of magnetic field. This magnetocaloric effect places YbPd2In as a very good candidate for adiabatic demagnetization cooling processes
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