Related papers: Magnetic Field Dependent Tunneling in Glasses
The thermal and dielectric anomalies of window-type glasses at low temperatures ($T<$ 1 K) are rather successfully explained by the two-level systems (2LS) standard tunneling model (STM). However, the magnetic effects discovered in the…
We have measured the low temperature electrical resistivity of Ag : Mn mesoscopic spin glasses prepared by ion implantation with a concentration of 700 ppm. As expected, we observe a clear maximum in the resistivity (T ) at a temperature in…
The effect of a magnetic field on the dipole echo amplitude in glasses (at temperatures of about 10 mK) induced by the dipole-dipole interaction of nuclear spins has been theoretically studied. It has been shown that a change in the…
Recently it has been experimentally demonstrated that certain glasses display an unexpected magnetic field dependence of the dielectric constant. In particular, the echo technique experiments have shown that the echo amplitude depends on…
In a recent manuscript, the discovery of a new phenomenon in glasses has been reported: {\it glass paramagnetism}, that is the intrinsic magnetisation developed by a substance that has failed to crystallise in a temperature quench when…
Domain walls in magnetic multilayered systems can exhibit a very complex and fascinating behavior. For example, the magnetization of thin films of hard magnetic materials is in general perpendicular to the thin-film plane, thanks to the…
The real part of the time-dependent ac susceptibility of the short-range Ising spin glass in a transverse field has been investigated at very low temperatures. We have used the quantum linear response theory and domain coarsening ideas of…
We present a theory for the memory effect in electron glasses. In fast gate voltage sweeps it is manifested as a dip in the conductivity around the equilibration gate voltage. We show that this feature, also known as anomalous field effect,…
We describe several experimental methods to quantify dynamics in electron glasses and illustrate their use in the glassy phase of crystalline indium-oxide films. These methods are applied to study the dependence of dynamics on temperature…
We report magnetization changes generated by an electric field in ferromagnetic Ga$_{1-x}$Mn$_x$N grown by molecular beam epitaxy. Two classes of phenomena have been revealed. First, over a wide range of magnetic fields, the magnetoelectric…
Time and history dependent magnetization has been observed in a wide variety of materials, which are collectively termed as the glassy magnetic systems. However, such systems showing similar non-equilibrium magnetic response can be…
We present new data on the nonequilibrium acoustic response of glasses to an applied dc electric field below 1K. When compared with the analogous dielectric response of the same material, the acoustic data show, within experimental…
The discovery of magnetic and compositional effects in the low temperature properties of multi-component glasses has prompted the need to extend the standard two-level systems (2LSs) tunneling model. A possible extension \cite{Jug2004}…
The novel isotope and magnetic effects on two level system echoes in glasses observed by Nagel et al.(Phys.Rev.Lett. 92, 245511 (2004)) provide unique experimental insight into the nature of tunneling systems in amorphous solids. We show…
When time-reversal symmetry is broken on its surface, topological insulators exhibit a magnetoelectric response which is described by axion electrodynamics. A direct consequence of this theory is the appearance of a magnetic field that…
The glass transition temperature (Tg) is the temperature, after which the supercooled liquid undergoes a dynamical arrest. Usually, the glass network modifiers (e.g., Na2O) affect the behavior of Tg. However, in aluminosilicate glasses, the…
We present a study of non-equilibrium phenomena observed in the electrical conductance of insulating granular aluminium thin films. An anomalous field effect and its slow relaxation are studied in some detail. The phenomenology is very…
A geometrically frustrated (GF) magnet consists of localised magnetic moments, spins, whose orientation cannot be arranged to simultaneously minimise their interaction energies. Such materials may host novel fascinating phases of matter,…
We investigate the effect of an applied magnetic field on resonant tunneling of electrons through the bound states of self-assembled InAs quantum dots (QDs) embedded within an (AlGa)As tunnel barrier. At low temperatures (no more than 2 K),…
The low temperature acoustic properties of bulk metallic glasses measured over a broad range of frequencies rigorously test the predictions of the standard tunneling model. The strength of these experiments and their analyses is mainly…