Related Experiment Video
Updated: Jul 16, 2026
20:38
AC Electrokinetic Phenomena Generated by Microelectrode Structures
Published on: July 28, 2008
Domain wall depinning in random media by ac fields.
A Glatz1, T Nattermann, V Pokrovsky
1Institut für Theoretische Physik, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany.
Physical Review Letters
|February 7, 2003
Summary
Interface motion in random media under AC fields shows a double hysteresis loop in the non-adiabatic regime. This phenomenon, absent in the adiabatic limit, is explained by scaling and renormalization group methods.
Area of Science:
- Physics
- Soft Matter Physics
- Complex Systems
Background:
- Understanding the dynamics of interfaces in disordered media is crucial for various physical phenomena.
- Driven interfaces in random media exhibit complex behaviors like depinning transitions.
Purpose of the Study:
- To investigate the non-adiabatic effects on the viscous motion of an interface driven by an AC external field.
- To explain the observed double hysteresis loop and its characteristics.
Main Methods:
- The study employs scaling arguments to analyze the interface dynamics.
- An approximate renormalization group calculation is utilized to model the system.
Main Results:
- The non-adiabatic regime reveals a smeared depinning transition with a double hysteresis loop.
- This double hysteresis is absent in the adiabatic (low frequency) case.
- The low-frequency limit of the hysteresis loop is characterized by the depinning threshold and adiabatic critical exponents.
Conclusions:
- The non-adiabatic AC field drives unique interface dynamics, leading to double hysteresis.
- Scaling arguments and renormalization group methods successfully explain these observed phenomena.
- The findings provide insights into driven interface behavior in disordered systems.
More Related Videos
Related Concept Videos
01:23Atomic Nuclei: Nuclear Relaxation Processes
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis. This...
01:16Electrostatic Boundary Conditions
Consider an external electric field propagating through a homogeneous medium. When the electric field crosses the surface boundary of the medium, it undergoes a discontinuity. The electric field can be resolved into normal and tangential components. The amount by which the field changes at any boundary is given by the difference between the field components above and below the surface boundary.
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
01:27Electrostatic Boundary Conditions in Dielectrics
When an electric field passes from one homogeneous medium to another, crossing the boundary between the two mediums imparts a discontinuity in the electric field. This results in electrostatic boundary conditions that depend on the type of mediums the field propagates through.
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's permittivity.
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's permittivity.
01:18Magnetic Field Due to Two Straight Wires
Consider two parallel straight wires carrying a current of 10 A and 20 A in the same direction and separated by a distance of 20 cm. Calculate the magnetic field at a point "P2", midway between the wires. Also, evaluate the magnetic field when the direction of the current is reversed in the second wire.
01:28Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
01:17Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...