Magnetic Properties of Solids and Their Applications

These flashcards cover key concepts and terms related to the magnetic properties of solids, their applications, and techniques in magnetism.

Diamagnetism

A property of all materials that opposes applied magnetic fields, exhibiting a very weak effect.

Paramagnetism

A magnetic property where materials produce magnetization in the direction of the applied field, which is stronger than diamagnetism.

Ferromagnetism

A magnetic property characterized by very large magnetizations, often much greater than the applied magnetic field.

Magnetization

A vector quantity expressing the density of net magnetic dipole moments in a material.

Magnetic Susceptibility (χ)

A dimensionless quantity that indicates how much a material will become magnetized in an applied magnetic field.

Magnetic Permeability (µ)

A measure of how a material responds to a magnetic field, defined as µ = 1 + χ.

Curie's Law

A law that relates the magnetic susceptibility of paramagnetic materials to temperature, stated as χ = C/T, where C is the Curie constant.

Soft Magnets

Materials that are easily magnetized and demagnetized, exhibiting high values of saturation magnetization.

Hard Magnets

Materials that exhibit high coercivity, being difficult to magnetize and demagnetize.

Curie Temperature (TC)

The temperature above which ferromagnetic materials become paramagnetic.

Magnetostriction

The change in dimensions of ferromagnetic materials during magnetization and demagnetization.

Electron Paramagnetic Resonance (EPR)

A method used to study paramagnetic substances by measuring the absorption of microwave radiation.

Nuclear Magnetic Resonance (NMR)

A physical phenomenon in which atomic nuclei absorb and reemit electromagnetic radiation in a magnetic field.

Functional MRI (fMRI)

An imaging technique that detects changes in blood flow and oxygenation in the brain to map brain activity.

Blood Oxygenation Level Dependent (BOLD) Imaging

A technique used in fMRI that relies on the differences in the magnetic properties of oxygenated and deoxygenated hemoglobin.

Voxel

A three-dimensional pixel representing a volume element in MR imaging.

Shimming

The process of adjusting the magnetic field in MRI to achieve uniformity and minimize inhomogeneity.

Contrast Agent

Substances used in MRI to enhance imaging quality by altering the relaxation times of protons.

Transition Metals

Elements known to have unfilled d-orbitals that often exhibit ferromagnetism.

Saturation Magnetization

The maximum magnetization that can be obtained in a material.

Magnetic Hysteresis

The lag between the magnetization of a ferromagnetic material and the applied magnetic field.