Related papers: On the Paramagnetic Impurity Concentration of Sili…
In this work we study the Kondo impurity problem - at a finite concentration of impurities. We identify two parameter regimes for the Kondo impurity problem. 1) The single impurity limit, where the concentration of Kondo impurities is so…
The tunnel magnetoresistance (TMR) of F/O/F magnetic junctions, (F's are ferromagnetic layers and O is an oxide spacer) in the presence of magnetic impurities within the barrier, is investigated. We assume that magnetic couplings exist both…
The study of quantum coherence in condensed matter systems is a broad avenue to be explored toward the enhancement of its quantum properties by means of material engineering. In this regard, the present work reports a study of the influence…
Dirty superconducting films with magnetic impurities can exhibit nontrivial behavior in a magnetic field that polarizes the impurity spins. As predicted by Kharitonov and Feigelman (KF) [JETP Lett. 82, 421 (2005)], this polarization reduces…
Exact results for the thermodynamic properties of ensembles of magnetic impurities with randomly distributed host-impurity couplings in the quantum antiferromagnetic Heisenberg model are presented. Exact calculations are done for arbitrary…
The ordering trend of magnetic impurities at low temperature results in the frustration of the pair-breaking effect and induces a ``recovery'' of superconducting properties. We show that this effect manifests itself in the deviation of the…
Susceptibility measurements of patterned thin films at sub-K temperatures were carried out using a scanning SQUID microscope that can resolve signals corresponding to a few hundred Bohr magnetons. Several metallic and insulating thin films,…
A core-softened model of a glass forming fluid is numerically studied in the limit of very low temperatures. The model shows two qualitatively different behaviors depending on the strength of the attraction between particles. For no or low…
Inhomogeneities of the field in the superconducting magnet of a superconducting quantum intereference device (SQUID) magnetometer can create serious artefacts in the d.c. magnetization measurements of superconducting samples. We discuss the…
It is found that in a wide range of temperatures and magnetic fields even a small concentration of magnetic impurities in a sample leads to a $T^{-1}$ temperature dependence of the nuclear heat capacity. This effect is related to a…
Magnetic impurities affect the spectrum of excitations of a superconductor and thus influence its impedance. We concentrate on the dissipative part of the surface impedance. We investigate its dependence on frequency, the density and…
Recent experiments demonstrated unexpected, even intriguing properties of certain glassy materials in magnetic field at low temperatures. We have studied the magnetic field dependence of the static dielectric susceptibility and the heat…
Amorphous solids, and many disordered lattices, exhibit a remarkable qualitative and quantitative universality in their acoustic properties at temperature $\lesssim 3$K. This phenomenon is attributed to the existence of tunneling two level…
Analyzing the atomic structure of glassy materials is a tremendous challenge both experimentally and computationally, and the lack of direct, detailed insights into glass structure hinders our ability to navigate structure-property…
The magnetisation relaxations of three different types of geometrically frustrated magnetic systems have been studied with the same experimental procedures as previously used in spin glasses. The materials investigated are Y$_2$Mo$_2$O$_7$…
Recent experimental results showing untypical nonlinear absorption and marked deviations from well known universality in the low temperature acoustic and dielectric losses in amorphous solids prove the need for improving the understanding…
We review recent experimental progress on the saturation problem in metallic quantum wires. In particular, we address the influence of magnetic impurities on the electron phase coherence time. We also present new measurements of the phase…
In a variety of different systems, high-Z ion species show a marked tendency to accumulate in regions of high plasma density. It has previously been suggested that the apparent universality of this behavior could be explained…
Interacting magnetic nanoparticles display a wide variety of magnetic behaviors that are now being gathered in the emerging field of 'supermagnetism.' We have investigated how the out-of-equilibrium dynamics in the disordered superspin…
To test basic assumptions inherent to most theories of molecular liquids and glasses, Infrared spectroscopy is carried out on short polyalcohols at temperatures ranging from far above to far below their glass transition. By analyzing…