What is Susceptibility: Definition and 79 Discussions

In electromagnetism, the magnetic susceptibility (Latin: susceptibilis, "receptive"; denoted χ) is a measure of how much a material will become magnetized in an applied magnetic field. It is the ratio of magnetization M (magnetic moment per unit volume) to the applied magnetizing field intensity H. This allows a simple classification, into two categories, of most materials' responses to an applied magnetic field: an alignment with the magnetic field, χ > 0, called paramagnetism, or an alignment against the field, χ < 0, called diamagnetism.
Magnetic susceptibility indicates whether a material is attracted into or repelled out of a magnetic field. Paramagnetic materials align with the applied field and are attracted to regions of greater magnetic field. Diamagnetic materials are anti-aligned and are pushed away, toward regions of lower magnetic fields. On top of the applied field, the magnetization of the material adds its own magnetic field, causing the field lines to concentrate in paramagnetism, or be excluded in diamagnetism. Quantitative measures of the magnetic susceptibility also provide insights into the structure of materials, providing insight into bonding and energy levels. Furthermore, it is widely used in geology for paleomagnetic studies and structural geology.The magnetizability of materials comes from the atomic-level magnetic properties of the particles of which they are made. Usually, this is dominated by the magnetic moments of electrons. Electrons are present in all materials, but without any external magnetic field, the magnetic moments of the electrons are usually either paired up or random so that the overall magnetism is zero (the exception to this usual case is ferromagnetism). The fundamental reasons why the magnetic moments of the electrons line up or do not are very complex and cannot be explained by classical physics. However, a useful simplification is to measure the magnetic susceptibility of a material and apply the macroscopic form of Maxwell's equations. This allows classical physics to make useful predictions while avoiding the underlying quantum mechanical details.

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  1. P

    Magnetic Susceptibility of different compounds

    Can anyone link me to a table of a large amounts of different compounds with the magnetic susceptibility of each one? Thanks.
  2. K

    Can anyone tell me abt magnetic susceptibility of fruits, vegetables,

    can anyone tell me abt magnetic susceptibility of fruits, vegetables, and herbs?, and related research papers
  3. J

    How Can I Calculate the Dielectric Susceptibility of Silicon Correctly?

    Hi everybody, i'm trying to calculate the dielectric susceptibility of Silicon (Si) using the formula \chi_{\vec g}=S(\vec g)(-\frac{\omega_p^2}{\omega^2})\frac{F(\vec g)}{Z}e^{-M} where S(\vec g) is the structure factor, \omega_p is the plasma frequency, \omega is the frequency...
  4. L

    Permeability, permittivity and susceptibility

    I got a little confused of these three things by my teacher and Griffiths. I am acquaintanced with Feynman's lectures on physics and what I get from there is \epsilon=\epsilon_{r}\epsilon_{0} = \left(1+\chi\right)\epsilon_{0} For some reason Griffiths, as well as my teacher, likes to use...
  5. H

    Magnetization of a material with linear susceptibility

    Fairly simple question: If a highly permeable material (of any shape) is placed in a uniform magnetic field, will the material's magnetization density always line up with the uniform magnetic field, or do I have to take into account the fields that are created as the material becomes...
  6. K

    Deviation from Curie-Weiss law in magnetic susceptibility

    Hi, I have some problems with interpretation of my dates of magnetic susceptibility measured on heavy compound Ce2RhIn8 doped by Pd on Rh site. The curves measured along c-direction follow the Curie-Weiss law only in the high temperature region (~200-300 K) and then deviate from it. The curves...
  7. FlexGunship

    Can Being Aware of Cognitive Biases Lessen Susceptibility to Bias Blind Spot?

    I've wondered this for a while: Can you decrease your susceptibility to decisioning yourself by becoming aware of self-deceptive practices? The reason this is not an open-and-shut case is because cognitive biases are unconscious, and therefore they cannot be consciously self-examined. In fact...
  8. F

    Compass and Magnetic Susceptibility

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  9. S

    Calculation of Magnetic susceptibility

    I wanted to calculate the magnetic susceptibility for a model system, with no interaction. I know the energy eigenvalues and eigenvectors. How can I proceed? Any help would be wonderful!
  10. F

    How Do We Calculate Magnetic Susceptibility Using Curie's Law?

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  11. G

    Magnetic susceptibility measurement

    Hi, I have to make a coil.I do not know anything about its dimensions but know that it is to be used to measure magnetic field,its actually to be used in a magnetic susceptibility measurement.There are 3 coils, drive, excitation, measurement and I/p is given at 1000hz frequency. I need to...
  12. R

    Simple ising model: Magnetic susceptibility derivation

    I'm stuck on a question about deriving an expression for the magnetic susceptibility in terms of the variance of the magnetisation for a simple 2d square ising model. I get the derivation of the specific heat, and I know am supposed to do something similar to get to the expression for...
  13. M

    Which Susceptibility of Bismuth Should I Calculate?

    I am trying to find the susceptibility for Bismuth, but I don't know which one I am after. Wikipedia gives molar, mass and volume. In my experiment we where asked to calculate the susceptibility, but not which one so I don't know which one I should compare with. In the experiment we used the...
  14. T

    Linear dielectric material. susceptibility

    Homework Statement I have a linear dielectric material. The electric field in the material is 38% less than a vacuum field with the same external sources. I need to find the susceptibility of the material? Homework Equations P= \chi(vacuum) E P= \chi(material) .62E...
  15. J

    Susceptibility dielectric material

    Homework Statement I have a linear dielectric material. The electric field in the material is 38% less than a vacuum field with the same external sources. I need to find the susceptibility of the material? Homework Equations I used P=\epsilon\chi(vacuum)E P=\epsilon\chi(material).62EThe...
  16. K

    Susceptibility: Imaginary Part = 0 - What Does it Mean?

    I am reading a paper on applying an external field on a two-level system. And it turns out that at some frequency (of the field), the imaginary part of the susceptibility become very close to zero. I wonder what's the physical significance when imaginary part of the susceptibility is ZERO...
  17. S

    Magnetic Susceptibility (Ferromagnetic)

    Homework Statement Near the critical point, Gibbs free energy of a ferromagnetic system can be written as (1). a)Using the definition of magnetization, (2), show that m(t,H=0) = Bt^{\beta} B is a constant. Determine \beta in relation to \alpha and \Delta b) Show that the...
  18. K

    Polarizaition and susceptibility

    In some unit, the relation of (linear) polarization and susceptibility can be written of P(t) = \chi E(t) but I also read some expression in other text reads P(\omega) = \chi(\omega) E(\omega) why change the time to frequency? Why polarization depends on frequency?
  19. G

    Magnetic susceptibility (Ising model)

    Hi, I'm slightly confused about how to prove that: \chi=\vartheta<M>/\varthetaH is equal to... \chi=(<M2>-<M>2 )/ T I've expressed <M> as \sumMsexp(-E/kBT) / \sumexp(-E/kBT) and know that E=-J\sumSiSj-H\sumSi But seem to get lost in the...
  20. T

    Susceptibility of low current circuits - OpAmp solution?

    I have what seems like a simple problem. I was asked to use a simple resistor divider as a scaling circuit into an A/D converter. My problem is that I have a low steady-state current requirement, and so I needed to increase the resistor values. I was told this is not an option because it...
  21. N

    Resonant and Non Resonant Susceptibility

    The imaginary part of the \chi ^3 susceptibility can be split into the resonant and non resonant contributions. The resonant is the contribution from satisfying a resonant vibrational state/mode, but what contributes to the non resonant term?
  22. D

    Magnetic susceptibility of ferromagnets

    Hi first post here. I was wondering if i could ask for some much needed help with a lab report I'm writing. It concerns Gadolinium metal. I was trying but failed to measure the magnetic field of gadolinium metal as a function of temperature from 77K to it's curie temperature of 293K. However...
  23. T

    Magnetisation and susceptibility

    Homework Statement 1. State a relationship between the free energy, F, and the magnetisation, M. 2. State a partition function for the case of a system of N independent spin-1/2 paramagnets in a field, and derive an expression for its susceptibility. The Attempt at a Solution (1) Looking in...
  24. B

    Finding magnetic susceptibility of a quantum gas

    Homework Statement H=H_{0} -g\muSB H_{0} = hamiltonian in absence of field S=Spin operator in the direction of the fied (say along z-axis) show that 1) M=1/\beta (dLn Z/ dB) 2) \chi = \beta(g \mu)^{2} <(S-<S>)^{}2> Dont know why it shows\mu in superscript. It isn't meant to be...
  25. P

    Electric susceptibility problem

    In a homogeneous linear dielectric , bound charge density \rho _b is proportional to free charge density \rho_f , because \rho _b = - \nabla \cdot \vec{P} = \frac{\chi_e}{1+\chi_e} \nabla \cdot \vec{D} = \frac{\chi_e}{1+\chi_e} \rho _f My problem is that bound charge density is...
  26. S

    Magnetic susceptibility question

    Not really a problem, I'm reading these 10 pages from a solid-state book for a professor, and it's a little over my head. Excuse the lack of LATEX but I copied it from another board I posted, and if you can help you likely know the equations involved anyways. I'm not expected to understand it...
  27. S

    Is Magnetic Susceptibility Dependent on Units?

    i think magnetic susceptibility xm=M/H is contant and independent of the units we are working with. in different refferences, they sometimes quote mks or cgs units which gives different value of Xm. It confuses me. Is Xm units dependent? for example Xm for oxygen is about 10^-4 in cgs...
  28. G

    What is particle-particle or particle-hole susceptibility

    what is particle-particle or particle-hole susceptibility in condensed matter physics? what is it good for and where does it come from?
  29. S

    Will Magnetic Susceptibility Depend on Direction in Atom Arrangement?

    Suppose there is a line of atoms X and Y. For atom Y, S = L = 0, but not for the atom X. The arrangement is like this: --X-Y---X-Y---X-Y---X-Y-- (periodical) In the following 2 cases, will the magnetic moment depend on whether the magnetic field is applied to the right or to the left? (The...
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