Related Experiment Video
Updated: Jan 2, 2026
09:43
Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement
Published on: November 7, 2017
9.8K
Dynamics of Magnetic Fluids in Crossed DC and AC Magnetic Fields
Alexander Pshenichnikov1,2, Alexander Lebedev1, Alexey O Ivanov3
1Institute of Continuous Media Mechanics UB RAS, 1, Korolyov str., Perm 614013, Russia.
Nanomaterials (Basel, Switzerland)
|December 6, 2019
Summary
This study models magnetic fluid dynamics in crossed magnetic fields. We show this method can estimate magnetic nanoparticle core size by analyzing output signals influenced by particle interactions and field frequencies.
Area of Science:
- Physics
- Materials Science
- Nanotechnology
Background:
- Magnetic fluids exhibit complex dynamics influenced by external magnetic fields.
- Understanding interparticle interactions and field-dependent relaxation times is crucial for characterizing magnetic fluids.
- Previous models often simplified these dynamic aspects, limiting predictive accuracy.
Purpose of the Study:
- To derive and validate equations for magnetic fluid dynamics in crossed magnetic fields.
- To investigate the influence of bias and probe fields on fluid behavior.
- To establish a method for estimating magnetic nanoparticle core size.
Main Methods:
- Derivation of dynamic equations considering field-dependent relaxation times, interparticle interactions, and demagnetizing fields.
- Experimental analysis of magnetic fluid samples (magnetite nanoparticles in kerosene) up to 80 kHz.
- Characterization of fluids with narrow and broad particle size distributions.
Main Results:
- The bias field induced short chain formation in monodisperse fluids.
- Quasi-spherical clusters (approx. 100 nm) formed in fluids with broad size distributions.
- A strong correlation between output signal and particle size was observed.
- The crossed field method successfully estimated maximum magnetic core diameter.
Conclusions:
- The derived equations accurately describe magnetic fluid dynamics under crossed fields.
- Particle size distribution significantly impacts cluster formation and fluid behavior.
- The crossed field technique offers a reliable, non-invasive method for nanoparticle sizing.
Related Concept Videos
01:28Magnetostatic Boundary Conditions
1.5K
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...
1.5K
01:27Magnetic Fields
7.0K
A moving charge or a current creates a magnetic field in the surrounding space, in addition to its electric field. The magnetic field exerts a force on any other moving charge or current that is present in the field. Like an electric field, the magnetic field is also a vector field. At any position, the direction of the magnetic field is defined as the direction in which the north pole of a compass needle points.
A magnetic field is defined by the force that a charged particle experiences...
A magnetic field is defined by the force that a charged particle experiences...
7.0K
01:23Magnetic Field due to Moving Charges
11.3K
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
11.3K
01:17Force On A Current Loop In A Magnetic Field
3.9K
Magnetic forces on wires carrying current are most frequently applied in motors. A DC motor is a device that converts electrical energy into mechanical work. In motors, wire loops are enclosed in a magnetic field. When current flows through the loops, the magnetic field applies torque, which causes the shaft to rotate. The direction of the current is reversed once the loop's surface area is lined up with the magnetic field, causing a constant torque on the loop. During the process, commutators...
3.9K
01:13Magnetic Force Between Two Parallel Currents
4.4K
Two long, straight, and parallel current-carrying conductors exert a force of equal magnitude on one another. The direction of the force depends on the current direction in the conductors.
The force exerted by the magnetic field due to the first conductor over a finite length of the second conductor is given as the product of the current in the second conductor and the vector product of the length vector along the current element and the field due to the first conductor. According to the...
The force exerted by the magnetic field due to the first conductor over a finite length of the second conductor is given as the product of the current in the second conductor and the vector product of the length vector along the current element and the field due to the first conductor. According to the...
4.4K
01:16Magnetic Field Of A Current Loop
6.1K
Consider a circular loop with a radius a, that carries a current I. The magnetic field due to the current at an arbitrary point P along the axis of the loop can be calculated using the Biot-Savart law.
6.1K