description
Magnetisation
Magnetization
VolumeMagnetisation
VolumeMagnetization
JoulePerCubicMeter
JoulePerCubicMetre
JoulePerMeter
JoulePerMetre
MegaJoulePerCubicMeter
MegaJoulePerCubicMetre
An EMMO-based domain-ontology for magnetic materials. Created within the EU project MaMMoS. Grant number 101135546 (HORIZON-CL4-2023-DIGITAL-EMERGING-01). The Magnetic Materials Ontology is released under the Creative Commons Attribution 4.0 International license (CC BY 4.0).
Magnetic Materials Ontology (MagMO)
Contacts: Wilfried Hortschitz DISS-UWK email: wilfried.hortschitz@donau-uni.ac.at
Created within the EU project MaMMoS. Grant number 101135546 (HORIZON-CL4-2023-DIGITAL-EMERGING-01).
Counts as a function of energy obtained from Energy-Dispersive X-ray spectroscopy.
EdxCounts
EDXCounts
Spatial extension along the principal axes.
GeometricalSize
Sequence of layers in a multilayer stack.
StackingSequence
The spontaneous magnetization, Ms, of a ferromagnet is the result of alignment of the magnetic moments of individual atoms. Ms exists within a domain of a ferromagnet.
SpontaneousMagnetization
SpontaneousMagnetisation
Local EDX data measured at a specific position.
LocalEdxData
LocalEDXData
Piece of matter made of one or more magnetic materials.
Magnet
The internal magnetic field -Hc at which the macroscopic magnetization vanishes is the coercivity or coercive force. Although it is not an intrinsic property in our sense of the term, the M-H loop coercivity Hc is sometimes referred to as 'intrinsic' coercivity.
CoercivityHc
CoerciveField
CoercivityHcInternal
CoercivityInternal
For a uniformly magnetized ellipsoid with magnetization along a major axis the demagnetizing field is Hd = -N M. The principal components of the diagonal demagnetizing tensor form the demagnetizing factors. Only two of the three are independent because the demagnetizing tensor has unit trace Nx + Ny + Nz = 1.
H = H' - DM, where D is the demagnetizing factor, M is the magnetization, and H is the internal field.
DemagnetizingFactor
DemagnetisingFactor
The essential practical characteristic of any ferromagnetic material is the irreversible nonlinear response of magnetization M to an imposed magnetic field H. This response is given by the hysteresis loop. The characteristics of hysteresis loop are known as hysteresis properties. Instead of M(H), other quantities can be used to plot a hysteresis loop. M(H): Magnetization as function of the internal field. M(H'): Magnetization as function of the external field. J(H): Magnetic polarization as function of the internal field. J(H'): Magnetic polarization as function of the external field. B(H): Magnetic flux density as function of the internal field. B(H'): Magnetic flux density as function of the external field.
MagneticHysteresisProperties
Local coercive field measured with the magneto-optic Kerr effect.
LocalCoercivity
Local profilometry data measured at a specific position.
LocalProfilometryData
Nonmagnetic thin film materials.
SpacerLayer
A material which is non-magnetic.
NonMagneticMaterial
Defined by the maximum slope of the descending branch of the M-H' hysteresis loop, with H' the external field.
SwitchingFieldCoercivityExternal
Volume of the unit cell.
CellVolume
UnitCellVolume
The magnetocrystalline constant K1 for tetragonal or hexagonal crystals.
Ea = K1 sin^2(phi) + K2 sin^4(phi) where Ea is the is the anisotropy energy density and phi is the angle of the magnetization with respect to the c-axis of the crystal.
MagnetocrystallineAnisotropyConstantK1
Description of ordered arrangement of atoms.
CrystalStructure
The angle between lattice vectors `a` and `c`, where lattice vectors `a`, `b` and `c` define the unit cell.
LatticeConstantBeta
LatticeParameterBeta
The Kerr signal (rotation or ellipticity) as a function of applied field obtained from MOKE measurement.
MokeKerrSignal
KerrSignal
MOKEKerrSignal
Counts as a function of 2theta angle obtained from X-ray diffraction.
XrayDiffractionData
Local annealing temperature from heat treatment such as Rapid Thermal Annealing (RTA).
LocalAnnealingTemperature
Magnetic anisotropy means that the magnetic properties depend on the direction in which they are measured.
MagneticAnisotropy
LineEnergyUnit
Unit of energy per unit length. Defined using SI base units.
wikipediaReference
The maximum working field - also named knee field H_K, is defined as the reverse external field for which the magnetization is reduced by 10%; thus it corresponds to the point on the magnetization loop for which M = 0.9 Mr (J = 0.9 Jr).
KneeFieldExternal
The internal loop squareness factor SF is defined as the ratio of the internal KneeField Hk over the internal Coercivity Hc (SF = KneeFieldInternal / CoercivityHcInternal).
LoopSquarenessFactorInternal
SF_internal
SquarenessFactorInternal
Ratio of the change of the magnetic moment per unit mass and the internal field: sigma = chi_m H.
MagneticSusceptibilityPerMassDensity
MassSusceptibility
The change of energy with angle of the magnetization from the preferred direction is expressed with the uniaxial anisotropy constant Ea = Ku sin²(theta).
UniaxialAnisotropyConstant
wikidataReference
Piece of matter made of stacked layers of one or more magnetic materials.
MultilayerMagnet
Relative direction of a crystallite in space with respect to another, disregarding distance.
CrystallographicOrientation
CrystalOrientation
Exchange constant, A, in the continuum theory of micromagnetism. The exchange stiffness A is related to the Curie temperature TC: A is roughly k_B T_c/(2 a_0), where a_0 is the lattice parameter in a simple structure.
ExchangeStiffnessConstant
The magnetocrystalline constant K1c for cubic crystals.
Ea = K1c(a1²a2²+a2²a3²+a1²a3²)+K2c(a1²a2²a3²) where Ea is the anisotropy energy density and a1,a2,a3 are the direction cosines of the magnetization
MagnetocrystallineAnisotropyConstantK1c
Local atomic percentage obtained from EDX quantification.
LocalAtomPercent
LocalAtomicPercent
at.%
Class of units of the magnetization per unit mass. Defined using SI base units.
MassMagnetizationUnit
MassMagnetisationUnit
SpecificMagnetisationUnit
SpecificMagnetizationUnit
The remanent magnetic polarization Jr which remains when the applied field is restored to zero in the hysteresis loop
RemanentMagneticPolarization
RemanentMagneticPolarisation
An additional phase within a magnet, for example soft inclusions or triple junctions.
SecondaryPhase
Standard deviation of the angle of the easy axis with respect to the alignment direction.
GrainMisalignmentAngle
Energy Density.
EnergyDensity
The 2theta angles at which the counts are measured during X-ray diffraction.
XrdTwoThetaAngles
XRDTwoThetaAngles
Kerr signal as a function of applied magnetic field obtained from Magneto-Optic Kerr Effect measurement.
MokeData
MOKEData
MagnetoOpticKerrEffectData
The standard deviation of the grain diameter of grains. Diameter is the diameter of a sphere with equivalent volume.
SigmaGrainSize
Change of the resistivity of a substance due to an applied magnetic field. Magnetoresistance can be defined as MR = [ϱ(B)-ϱ(0)]/ϱ(0).
Magnetoresistance
Local phase fraction obtained from XRD analysis, typically expressed in weight percent.
LocalPhaseFraction
LocalPhaseContent
A spacegroup is the symmetry group of all symmetry operations that apply to a crystal structure. The complete symmetry of a crystal, including the Bravais lattice and any translational symmetry elements, is given by one of the 240 space groups. A space group is identified by its Hermann-Mauguin symbol or space group number (and setting) in the International tables of Crystallography.
SpaceGroup
Magnetic moment per unit mass, sigma.
The magnetization is obtained by multiplying sigma with the density
MagneticMomentPerUnitMass
MassMagnetisation
MassMagnetization
SpecificMagneticMoment
The magnetocrystalline constant K2 for tetragonal or hexagonal crystals.
MagnetocrystallineAnisotropyConstantK2
Any amorphous structure entails a distribution of nearest-neighbour environments and bond lengths for a given magnetic atom, described by the radial distribution function and higher-order correlation functions. These distributions lead to a distribution of site moments, exchange interactions, dipolar and crystal fields, all of which influence the nature of the magnetic order.
AmorphousMagneticMaterial
Defined as internal field on the B(H) loop where B = 0. It is also called flux coercivity BHc. BHc depends on sample shape and has to be corrected for the demagnetizing field.
CoercivityBHc
Height profile as a function of distance obtained from profilometry measurement.
ProfilometryData
Local X-ray diffraction data.
LocalXrayDiffractionData
The anisotropy can be described as uniaxial when the anisotropy energy E depends on only a single angle, the angle between the magnetization vector and the easy direction of magnetization.
UniaxialMagneticAnisotropy
Piece of matter made of one or more magnetic material in form a thin film.
ThinFilmMagnet
The uniaxial anisotropy depends on only a single angle, the angle magnetization vector and the c axis.
UniaxialMagnetocrystallineAnisotropy
Energy per unit length.
LineEnergy
EnergyPerLength
EnergyPerUnitLength
Ensemble of grains of 1 or more grains.
GranularStructure
The external loop squareness factor is defined as the ratio of the external KneeField H'k over the external Coercivity H'c (SF' = KneeFieldExternal / CoercivityHcExternal).
LoopSquarenessFactorExternal
SF_external
SquarenessFactorExternal
The height profile as a function of distance obtained from profilometry measurement.
ProfilTotalProfile
PROFILTotalProfile
Material separating grains in a microstructure.
In permanent magnets, the grain boundary phase inhibits the propagation of the magnetic reversal from grain to grain.
GrainBoundaryPhase
Main phase of the magnet
MainMagneticPhase
Extrinsic magnetic Properties depend on the microstructure.
ExtrinsicMagneticProperties
The Saturation magnetic polarization Jsat is the maximum obtainable magnetic polarization for a given substance at a given temperature. Jsat should be used instead of Js to avoid confusion with the symbol for the spontaneous polarization
SaturationMagneticPolarization
Jsat
SaturationMagneticPolarisation
The mean of the grain diameter of grains. Diameter is the diameter of a sphere with equivalent volume.
MeanGrainSize
EnergyDensityUnit
Unit of energy density. Defined using SI base units.
The remanence Mr which remains when the applied field is restored to zero in the hysteresis loop
Remanence
RemanentMagnetisation
RemanentMagnetization
The applied magnetic field values during MOKE measurement.
MokeAppliedField
MOKEAppliedField
Ratio of the change of magnetic flux density and the internal field: B = mu H.
AbsolutePermeability
The length of lattice vectors `c`, where lattice vectors `a`, `b` and `c` define the unit cell.
LatticeConstantC
LatticeParameterC
The length of lattice vectors `b`, where lattice vectors `a`, `b` and `c` define the unit cell.
LatticeConstantB
LatticeParameterB
The angle between lattice vectors `a` and `b`, where lattice vectors `a`, `b` and `c` define the unit cell.
LatticeConstantGamma
LatticeParameterGamma
A dimensionless fourth-order cumulant of magnetization, defined as U4 = 1 − <m^4>/(3 <m^2>^2), where m is the normalised magnetization (magnetization per site). It is used in finite-size scaling as an approximately scale-independent measure of critical fluctuations: curves for different system sizes intersect near the phase-transition temperature, enabling estimation of Tc without direct extrapolation to infinite system size.
Binder, K. (1981). "Finite size scaling analysis of ising model block distribution functions". Zeitschrift für Physik B: Condensed Matter. 43 (2): 119–140. https://doi.org/10.1007/bf01293604
BinderCumulant
BinderParameter
The Saturation magnetization Msat is the maximum obtainable magnetic magnetization for a given substance at a given temperature. Msat should be used instead Ms to avoid confusion with the symbol for the SpontaneousMagnetization
SaturationMagnetization
Msat
SaturationMagnetisation
Defined as external field on the B(H') loop where B = 0. H' is the external field.
CoercivityBHcExternal
Geometric shape. Two extrinsic properties, the remanence Mr and coercivity Hc, which depend on the sample shape
GeometricShape
Magnetic material with crystalline structure.
CrystallineMagneticMaterial
Ratio of the change of magnetization and the internal field: M = chi H.
InternalSusceptibility
The energy density of a small particle given by K1sh = (mu_0/4)(1-3D)Ms² where mu_0 is the vacuum magnetic permeability and D is the DemagnetizingFactor and Ms is the spontaneous magnetization.
ShapeAnisotropyConstant
The magnetic field produced by the magnetization distribution of the sample itself.
DemagnetizingField
DemagnetisingField
The maximum working field - also named knee field H_K, is defined as the reverse internal field for which the magnetization is reduced by 10%; thus it corresponds to the point on the magnetization loop for which M = 0.9 Mr (J = 0.9 Jr).
KneeField
KneeFieldInternal
MaximumWorkingField
Function representing relative sizes of grains in a system. Given by its mean and standard deviation of a lognormal distribution
GrainSizeDistribution
ParticleSizeDistribution
Cubic crystals anisotropy.
CubicMagnetocrystallineAnisotropy
Standard deviation of the grain misalignment angle in an ensembles of misaligned magnetic particles. This refers not only to isotropic magnets but also to partly aligned or textured magnets, where the easy-axis distribution is described by a function P(theta).
EasyAxisDistributionSigma
Intrinsic magnetic properties refer to atomic-scale magnetism and depend on the crystal structure.
IntrinsicMagneticProperties
A grain is a small or even microscopic crystal which forms, for example, during the cooling of many materials.
Grain
Crystallite
The energy values at which the counts are measured during Energy-Dispersive X-ray spectroscopy.
EdxEnergy
EDXEnergy
The angle between lattice vectors `b` and `c`, where lattice vectors `a`, `b` and `c` define the unit cell.
LatticeConstantAlpha
LatticeParameterAlpha
The internal field in the sample in the continuous medium approximation is the sum of the external field H′ and the demagnetizing field Hd.
InternalMagneticField
The size and shape of the magnet
SampleGeometry
Local MOKE data measured at a specific position.
LocalMokeData
LocalMOKEData
A rectangular cuboid is a special case of a cuboid with rectangular faces in which all of its dihedral angles are right angles.
RectangularCuboid
Three angles introduced by Leonhard Euler to describe the orientation of a rigid body with respect to a fixed coordinate system.
EulerAngles
Defined by the maximum slope of the descending branch of the M-H hysteresis loop, with H the internal field.
This field is often used when analysing the temperature dependent coercivity for deriving microstructural parameters.
SwitchingFieldCoercivity
Magnetocrystalline anisotropy is an intrinsic property. The magnetisation process is different when the field is applied along different crystallographic directions, and the anisotropy reflects the crystal symmetry. Its origin is in the crystal-field interaction and spin-orbit coupling, or else the interatomic dipole–dipole interaction.
MagnetocrystallineAnisotropy
Local reflectivity measured with the magneto-optic Kerr effect.
LocalReflectivity
The magnetocrystalline constant K2c for cubic crystals.
MagnetocrystallineAnisotropyConstantK2c
The distance values along the scan direction during profilometry measurement.
ProfilDistance
PROFILDistance
Magnetically ordered solids which have atomic magnetic moments due to unpaired electrons.
MagneticMaterial
The length of lattice vectors `a`, where lattice vectors `a`, `b` and `c` defines the unit cell, measured locally.
LocalLatticeConstantA
2D array containing all pixel intensities from a 2D XRD camera. This is the raw XRD data from which 1D spectra are obtained.
Xrd2dImage
XRD2DImage
XRD2dImage
Xrd2DImage
The anisotropy field Ha is defined as the field needed to saturate the magnetization of a uniaxial crystal in a hard direction. Ha = 2 Ku/Js
Beware of taking the idea of anisotropy field too literally. Except at small angles, the energy variation in a field is not the same as the leading term in the anisotropy. A magnetic field defines an easy direction, not an easy axis.
AnisotropyField
The granular structure of a magnetic materials.
GranularMicrostructure
Piece of matter made of one or more magnetic material.
BulkMagnet
Local annealing time (duration) from heat treatment such as Rapid Thermal Annealing (RTA).
LocalAnnealingTime
LocalAnnealingDuration
Capacity of an object to reflect light.
Reflectivity
Reflectance
Ratio of the change of magnetization and the external field: M = chi' H'.
ExternalSusceptibility
The external field H′, acting on a sample that is produced by electric currents or the stray field of magnets outside the sample volume, is often called the applied field.
ExternalMagneticField
AppliedMagneticField
The spontaneous magnetic polarization, Js, of a ferromagnet is the result of alignment of the magnetic moments of individual atoms. Js exists within a domain of a ferromagnet.
SpontaneousMagneticPolarization
SpontaneousMagneticPolarisation
The length of lattice vectors `c`, where lattice vectors `a`, `b` and `c` defines the unit cell, measured locally.
LocalLatticeConstantC
Unit of the magnetic moment per unit mass: Am²/kg.
AmpereSquareMeterPerKilogram
AmpereSquareMetrePerKilogram
XrdCounts
XRDCounts
The value of the maximum energy product (BH)max is deduced from a plot of BH(B) for all points of the second quadrant of the B-H hysteresis loop. BH varies with B going through a maximum value (BH)max for a particular value of B. (BH)max equals the area of the largest second-quadrant rectangle which fits under the B-H loop. The maximum energy product is considered to be the best single index of quality of a permanent magnet material. It is twice the energy stored in the stray field of the magnet of optimal shape.
MaximumEnergyProduct
EdxData
EDXData
EnergyDispersiveXraySpectroscopyData
The magnetocrystalline anisotropy energy density.
MagnetocrystallineAnisotropyEnergy
Uniaxial anisotropy induced by annealing in a magnetic field or by applying a stress.
InducedMagneticAnisotropy
IECEntry
The length of lattice vectors `a`, where lattice vectors `a`, `b` and `c` define the unit cell.
LatticeConstantA
LatticeParameterA
The thickness of the film measured locally.
LocalThickness
The external loop squareness is defined as the ratio of the remanent polarisation over the saturation polarisation (SS = RemanentMagneticPolarization / SaturationMagneticPolarization).
LoopSquareness
Squareness
The difference in magnetostatic energy when an elongated particle is magnetized along its short and long axis.
Shape anisotropy is restricted to small particles, where the inter-atomic exchange ensures a uniform magnetization.
ShapeAnisotropy
The external magnetic field -H'c at which the macroscopic magnetization vanishes. The coercivity on M(H') loop, where H' is the external field.
CoercivityHcExternal
Local mass percentage obtained from EDX quantification.
LocalMassPercent
LocalWeightPercent
wt.%