Measurements

Our magnetic measurement business serves an important role in technology,  product development and engineering applications for many large and small businesses including many Fortune 100 companies, Universities, Medical institutions and many more in both domestic and international markets.

ARkival’s VSM Group is considered as the premier magnetic contract measurement company with expertise in all aspects of magnetic materials and their applications.

Our large, prestigious and established client base seeks our magnetic measurement expertise that extends from magnetic field measurements to materials and devices with many applications in the form of magnetic solids, liquids and thin films.

We maintain a well-equipped Magnetic Testing Laboratory that provides full service magnetic testing capability for all your magnetic applications, material evaluations and product testing. Our supporting Physics and Chemistry labs are fully equipped to service the needs of all types of magnetic applications, magnetic nanotechnologies, magnetic products and their evaluations, component make-up and performance analyses. Our services include sample preparations, magnetic evaluation, supporting analysis, modeling and simulations among many others client requirements.

ARkival’s VSM’s and torque magnetometers and a multitude of Hall Effect probes provides for magnetic measurements of magnetic materials used for all applications. Our independent measurement laboratory tests magnetic materials including thin films, ferrites, powders, concretes, magnetic liquids and gels, nanotechnology products, magnetic platings, particles, beads and tapes, discs, wires and permanent magnets (both iron-based and rare-earth materials). Our services include simple magnetic parameter data, quality and assurance data, magnetic analysis, custom measurements and full analytic reports.

 

 

Here for your needs

From the magnetic domains to the particles, to the powders, fluids, and vapor deposited materials… to the thin films, solids, and dispersions… to the plating’s, coatings, tracers…. to the products, production and applications, ARkival Technology is your source of magnetic expertise.

Types of Measurements

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Magnetic Properties

ARkival’s VSM magnetometers and a multitude of Hall Effect probes provides magnetic measurements of magnetic materials used for all applications. Our independent measurement laboratory can test any magnetic material including thin film, ferrites, powders, magnetic liquids and gels, nanotechnology products, magnetic platings, particles and tapes, discs, and permanent magnets (both iron-based and rare-earth materials). Our services included simple magnetic test data, quality measurements and assurance data, magnetic analysis, custom measurements all provided with optional analytic reports.

Magnetic Parameters* tested can include the following:

Bs, Br, Hc, Hr, Sq, SFDr, SFD, Hmax, Is, Ir, SQ, S*, Hc, dH, SFD

Our Laboratory is equipped with several digital Microsense/ADE/DMS Vibrating Sample Magnetometers, a torque magnetometer and a Lakeshore/PAR VSM all networked to a computer-controlled magnetic measurement system to accurately characterize magnetic materials including single phase, bi-phase, anisotropic, diamagnetic, paramagnetic, and ferromagnetic and many other magnetic material types. The computer controlled VSM test process provides automatic sequencing of different types of magnetic measurements including field-ranging capability. Testing can be customized for specific applications based on sample size, test fields, measurement planes and temperatures. Our specialized test equipment uses ARkival’s custom-developed software that can be tailored to any customer requirement and measurement. 

ARkival is committed to providing fast turnaround service and offers secured web access to your data and test measurements. Our main business is measurements and we seek to provide effective and meaningful data for your magnetic applications.

Measurements & Turnaround time

  • Standard testing: 48 hours after sample receipt
  • Expedited testing: 24 hours maximum after sample receipt
  • Loop expansions
  • Alternative parameters and temperatures
  • Sample preparation and sizing
  • Special tooling for odd-sized samples
  • Written reports, commentaries

 

Applications that we Support

  • Magnetic Resonance Imaging
  • Medical Contrast Agents
  • Magnetic Drug Delivery carriers
  • Ferrites, magnetic powders and toners
  • Permanent magnets
  • Mu Metals
  • Stainless Steels
  • Inks and ferrofluids
  • Organic materials
  • Magnetic tapes and discs
  • Magneto-optical materials
  • Platings, thin films
  • Turnpike tickets
  • Credit cards
  • Steels
  • Superconductors

Supplemental & supporting Measurements

In recent years we have developed an expertise in “Magnetic Material Fingerprinting” such that a specific combination of our services are used to identify inorganic (and some organic) materials and particles extending from discrete nanoparticles used in magnetic contrast agents for medical MRI testing and human drug delivery to the miniature data storage components and vapor deposited thin films used in GPS’s, smart cell phones, computers and semiconductor devices.

This analytic technology incorporates our chemical, physics, electronics and material expertise that is coordinated with our years of experience with magnetic materials and products.  It includes using advanced analytic equipment such as Vibrating Sample Magnetometers, Magnetic Force Microscopy, Scanning & Transmission electron microscopy, Electron Diffractometry, SP Particle sizing and materials identification, etc.

Our services vary from simple parameter measurements of materials to small or large consulting projects that pertain to material problem solving, reverse-engineering and product design and development. An all-important aspect of our services has been the expediency of the solutions and technology we bring to solve problems as we understand manufacturing demands, product performance and failure and the ramifications of fast and accurate solutions.

*see ISO spec in section below “and more”

Permeability (μ)*

Permeability numbers are often stated in specifications and product sheets can result from handbooks and web-searches with little understanding of the measurement process, temperature effects, the definition and application and the lack of standardization and calibrations that are all required for accurate and repeatable permeability data. Listed below are the more common, yet very different definitions for Permeability.

About Permeability

Magnetic permeability can be envisioned as ‘conductivity for magnetic flux‘; and materials with high permeability’s allow magnetic flux through more easily than materials with lower permeability’s. Materials with high permeability’s include iron and the other ferromagnetic materials. In comparison, most plastics, wood, non ferrous metals, air and other fluids have very low permeability’s.

Unlike electrical conductivity, magnetic permeability is often a highly non-linear quantity although many designers use it as a constant and accept the inaccuracy of treating a non-linear quantity as linear.

Absolute permeability

reported in units of Henry’s per meter (H m-1)

The magnetic permeability, μ, of a particular material is defined as the ratio of flux density (magnetic moment-B) to applied magnetic field strength-H:

μ = B / H

This magnetic data is typically obtained from the magnetization curve.

The magnetic permeability is often a highly non-linear quantity although many specifications use it as a constant and do not accept inaccuracy of treating a non-linear quantity as linear.

This form of permeability, where μ is written without a subscript, is reported in  SI units as the Absolute permeability.

Relative permeability (μr)

reported dimensionless

The most commonly used engineering term for permeability is that of Relative permeability described as

μ = μ0 × μr

This form of permeability is usually written with subscripts.

Relative permeability is a variation of absolute permeability, μ, but often perceived more useful because it demonstrates how a particular material affects the relationship between flux density (magnetic moment) and applied field strength. The term ‘relative’ relates to the permeability of a vacuum, μ0

μr = μ/μ0

For example, a material with μr = 3 suggests that the flux density will be three times as great as it would be if we just applied the same field strength to a vacuum.

Many authors and data tables  report “permeability” and leave the reader to infer that they mean relative permeability. In the CGS system of units these are one and the same. If a figure greater than 1.0 is quoted then you can be almost certain it is μr.

Differential permeability (μ′)

reported dimensionless

‘Absolute permeability’ defined above is not the same as the slope of a tangent line to the B-H curve except at the peak (around 80 A m-1 in this case). The latter is called Differential permeability, where

μ′ = dB/dH

 The Differential Permeability is calculated and reported by ARkival for material Permeability measurement as X init, X max and X90%.

 

Also of note is temperature dependence on permeability reporting. For example,  if the sample temperature is increased e.g., 20 to 80 centigrade,  a typical ferrite can suffer a 25% drop in relative permeability which is also a significant consideration for applications.

Initial permeability (μi)

reported dimensionless

Magnetic Permeability measurements are obtained from a fully erased sample. Unlike Hysteresis loop measurements, ARkival performs this measurement from a fully erased sample state and applies the magnetizing field (H) until material saturation is demonstrated- whereby sample magnetization is only recorded and presented in a single quadrant.

Initial permeability describes the relative permeability of a material at low values of applied Field B (below 0.1T) whereas the maximum value for μ in a material is frequently a factor of between 2 and 5+ above its initial value.

The Initial (Differential) Permeability reported by ARkival for material Permeability measurement as X init (see discussion above). 

 

Effective permeability (μe)*

reported dimensionless

Effective permeability is reported in some data sheets for cores which have air gaps. Coil calculations ignore the air gap by assuming use of a material whose permeability is lower than the material used.

For additional information please contact ARkival.

*http://info.ee.surrey.ac.uk/Workshop

 

Curie Temperature

mta-studies_1445x400

 

ARkival’s Curie temperature (TC), or Curie point measurements are designed to determine the critical temperature at which magnetic materials loose their permanent magnetic properties. Controlled temperature tests are performed in inert gas environments to determine the temperature (or temperature range) for which magnetic losses occur and the temperature below which magnetic properties return.

The determination of a magnetic materials’ Curie temperature is the point or temperature region which a material’s intrinsic magnetic moments disorient and randomly change direction.

Our lab facilities and magnetometers enable us to apply external magnetic fields during a controlled high temperature heating process while preventing material oxidation in an inert gas environment.

Magnetic Fields & Field Mapping

ironfilings_1445x400

Magnetic Field Mapping  

Many magnet applications use permanent magnets or electromagnets to provide a magnetic field for an attractive or repulsive interaction. Magnetic field data is required for product designs and applications where product function is based upon magnetic strength, the magnetized pole geometry, the external field shape and magnitude at the working distance(s) in the application. A magnetic field map can provide the effective magnetic field characteristics of application magnet(s).

ARkival performs field mapping measurements to determine magnetic field forces, field directions and distributions, and magnetic edge effects. Planar-probes or edge-directed Hall probes are used with a custom designed micrometer measurement mapping fixture to provide 3Dimensional micrometer-stepped planar field maps. The resulting field maps provide both the shape and magnitude of the magnetic field at different points and in 3 planar surfaces as well as at varying distances from the primary magnetic source.

Field Measurements & Distance mapping

Magnetic field data can be collected in 1, 2 or 3 planes (X, Y & Z) at both the magnet center and magnet edges. The application magnets are positioned in a non-magnetic stand custom-machined for these measurements. The Hall-effect probes are mounted in a 3D micrometer station providing accurate dimensional stepping in 3-planar directions. Hall-effect probes are periodically calibrated with 2 traceable reference magnets throughout the measurement collection.

Thermal Properties

ARkival offers several services to meet you Thermal Property measurement needs.  Contatc us at 603.881.3322 for more information.

 

Dielectric Properties

ARkival offers several services to meet you Dielectric Properties measurement needs. Contact us at 603.881.3322 for more information.

 

Hall Effect Measurements

ARkival has an extensive range of different types and configurations of Hall effect probes. Contact us at 603.881.3322 for more information.

ALSO See Discussions in Magnetic Fields & Field Mapping  AND Geomagnetic Measurements

Geomagnetic Measurements

ARkival Technology performs Magnetic Field testing of magnet-contained products designated for both domestic and international air shipments.  Such products are required to be magnetically source-distance-tested for compliance to the required ICAO & IATA 1 specifications.

The resulting source-distance data requires magnetic fields less than the maximum value specified by ICOA & IATA documents at the seven (7’) foot and fifteen (15’) foot distances for all packaged and non-packaged products with magnets.  ARkival’s testing process delivers actual and simulated worst-case magnetic field measurements to determine the cumulative field effect (magnetic field strength and magnetic polarity) of the magnet and/or magnetic materials at required planes and distances.

ARkival’s Testing includes…

Project Description for testing, evaluating and certifying shipping cartons containing Magnets and/or magnetic devices for compliance to the ICAO guidelines for the safe transport by air.

Reference Documents: International Civil Aviation Organization (ICAO) Standards and regulations for aviation safety, security, efficiency, regularity and aviation environmental protection.

ICAO standards and other provisions: Standards and Recommended Practices (SARPs)

  • Packing instruction: reformatted packing instructions (effective 1 January 2011) v; 6 P141 (17/10/2008) 2– and subsequent releases.
  • Technical instructions for the safe transport of dangerous goods by air: 2011-2016 edition doc9284-an/905 add #3.crr. #2 26/4/11 and subsequent releases.
  • IATA- Dangerous Goods Regulations- Magnetic products

Specific Testing

ARkival’s test procedure addresses the class of materials on passenger and Cargo aircraft designated as UN 2807, Magnetized material

Measurements determine the magnetic field strength at the both distances of 2.1 m (7 ft.) and 4.6 m (15 ft.) from any point on any surface of the individually packaged unit with 360 degree rotations in two planes.

For compliance, we determine that magnetic field readings resulting from tested product(s) at the specified distances and orientations do not exceed 0.159 A/m and 0.418 A/m respectively.

Measurement Equipment

All magnetic field measurements are made with Hall Effect probes with either linear or transverse sensors3. The laboratory test area is free from magnetic interference other than the earth’s magnetic field (~ 5 milliGauss-mG at the EW measurement (geographic) location when minimized).

The primary Hall effect Gaussmeters are all Geomagnetometers used with calibrated Probe Reference Standards. Distance measurements are all supported by a Class IIIA Laser Tape.

1 ICAO- International Civil Aviation Organization (www.icao.int) & IATA- International Air Transport Association (www.iata.org).
http://www.iata.org/SiteCollectionDocuments/Documents/IATARefomattedPacking
3 The use of a highly sensitive, CMOS technology Hall probes for these measurements requires additional humidity and stray earth field shielding during testing.

 

Torque Measurements

 torque-measurement

ARkival’s Torque Measurements are performed with a MicroSense VSM employing an ultra-low friction, air bearing suspending the sample with virtually zero friction. The resulting torque measurement reports the actual force on the sample. All pre-measurement calibrations are directly based upon a known torque sample. ARkival’s magnetic torque measurements can accommodate solid, bulk, and thin film samples with a torque measurement capability from 0.05 dyne-cm to 500 dyne-cm depending upon the sample magnetics, applied field, sample type and size.

Direct Magnetic torque measurements can, in some samples be more sensitive than SQUID magnetometry as our direct torque measurement is more precise and more sensitive than an indirect vector coil-based torque system.

Whereas torque is a measure of the sample’s magnetic or shape anisotropy, the magnetic torque measurement can detect magnetic phase transitions or quantum oscillations. Under certain conditions, the sample magnetization can also be extracted from the measured torque.

 

Magnetic Thermal Annealing (MTA)

mta-studies_1445x400

ARkival’s Magnetic Thermal Annealing (MTA) process is used to enhance the performance of  magnetic materials and components. During their manufacture, preparation and processing the crystalline and magnetic  structures of these materials can assume moderate to high degrees of disorder.  The process of controlled  magnetic thermal annealing can remove these disorders and can often provide substantially improved magnetic performance of the materials and even their devices (e.g., spintronic devices).

The heating a magnetic material above its recrystallization temperature in a magnetic field and then cooling will allow atom migration within the crystal lattice such that the number of dislocation sites decreases, leading to the change in magnetic properties and at times, their ductility and hardness.

Magnetic materials such as  metals (in different shapes and forms… wires, foils and plates), powders and thin films can be thermally treated in temperatures up to 900˚C  in a uniform magnetic field (as high as 2.5 Tesla) and in an inert gas environment for MTA processing.

Environmental Testing

ARkival’s facilities house several environmental chambers for small-to-medium sized products, components and test systems. The chambers are equipped to provide acclimatization cycling with real-time temperature and humidity monitoring. The chambers are designed for flexibility and can be configured for special product requirements and testing during environmental exposure.

SEM (Scanning Electron Microscope)

sem-mnps-2

Scanning electron microscopy (SEM) is a very high imaging magnification performed with an electron microscope that produces informative images of magnetic samples by scanning them with a focused beam of electrons. The electrons interact with atoms in the sample, producing highly magnified images of the sample’s surface topography and composition.

Image Magnification from a SEM can be controlled from 10 to 300,000 times. In magnetics, ARkival uses SEM micrograph images regularly to study minute structures, nanoparticles, minute structural detail, surface areas of materials, biological specimens and more.  See MNP images-

TEM (Transmission Electron Microscope)

tem-mnps-1

Transmission electron microscopy (TEM) is a very high imaging magnification also performed with an electron microscope  to view thin material cross-sections and specimens (nanoparticles, tissue sections, molecules, etc) through which electrons can pass generating a projection image. TEM is analogous in many ways to the conventional (compound) light microscope with greater magnification and detail.

 

Image Magnification from an TEM can be controlled from 10 to 300,000 times. In magnetics, ARkival uses TEM micrograph images regularly to study minute structures, nanoparticles, minute structural detail and more.  See MNP images

EDAX (Energy Dispersive Analysis by X-Ray (EDX, EDS)

 

graph

EDX Data Spectrum 

A typical EDX SPECTRA (elemental) result is shown below. The elemental spectral peaks are identified during the x-ray scan. The individual elements are indicated in the spectra by both their intensity and position. The greater the intensity, the higher the element concentration in the sample. Missing or additional elements are determined from a comparison of the individual sample data.

The spectra below illustrate the elemental results for 2 samples from the same grouping. Both these samples contain significant amounts of Iron (Fe) and Cobalt (Co). Although these primary magnetic elements are present in all three sample groups, their weight percents vary- particularly when comparing one to another group.

The superpositioning of the spectra shown below (and all others) are summarized in the clients’ analysis reports.

The elemental weight percents (Figure below) for each of the samples is also collected. Data from these result Tables are used to identify and illustrate differences. Similarities and differences are best be identified by the weight percentage results from the following sample reports. The comparative elemental analysis of the different samples is included in the Summary section of the customer report.

 

ICP (Inductively Coupled Plasma Mass Spectrometry)

ICP Atomic Emission Spectroscopy (ICP-AES AnalysisICP-AES is a measurement technique that ARkival uses to determine elemental concentrations in minute trace amounts to major compositions. Statistical concentration data results can be obtained for about 70 elements with detection limits in the parts per billion range.

Inductively coupled plasma (ICP) mass spectrometry (ICP-MS) measurements are a type of mass spectrometry ARkival uses that is capable of detecting metals and several non-metals at concentrations as low as one part in 1015 (part per quadrillion, ppq). It is used in tissue containment analysis involving exceptionally small diagnostic and treatment material quantities and types.

MFM (Magnetic Force Microscopy)

MFM Measurements (Magnetic Force Microscopy)

MFM is a magnetic measurement technology for imaging various magnetic structures including magnetic domains, domain walls (Bloch and Neel), recorded magnetic bits and magnetic surface structures and abnormalities. MFM studies can also be made with and without the presence of an external magnetic field.

MFM imaging of various materials such as thin films, nanoparticles, nanowires, permalloy disks and recording media are commonly performed. The technology does not require the sample to be electrically conductive and measurements are performed at ambient temperature, in ultra-high vacuum (UHV), in a liquid environment, at different temperatures, and in the presence of external magnetic fields.

The Measurement is nondestructive to the crystal lattice or structure and is typically insensitive to minor surface contamination. No special surface preparation or coating is required.

Sample are usually scanned twice. The first scan of the surface presents the topography of the sample. In secondary scans, the magnetic tip-sample distance is increased and when scanned along the topography line is only affected by the magnetic forces. The signals are electronically configured to obtain the MFM image.

This form of cantilever magnetometry (MFM) can also be used for characterizing magnetic samples and as technique to characterize the magnetic properties of materials and measure the magnetic dissipation in magnetic materials. The magnetization of individual magnetic nanoparticles (MNP) can also be determined with MFM for future applications in nanomagnetism and biotechnology.