Measurements of low-field magnetic susceptibility on discrete samples
Susceptibilitymeter MFK2-FA (AGICO) for the measurement of low-field susceptibility, its frequency dependence and its anisotropy
Instrument description:
The MFK2-FA susceptibilitymeter measures low-field susceptibility at three different frequencies (916, 3904 and 15616 Hz) and at variable fields (2 to 700 A/m). With a sensitivity of 2.10-8 SI (at low frequency), it is suitable for discrete samples of various types and up to several centimetres in size. The device also allows to precisely determine the tensor of the anisotropy of magnetic susceptibility using a rotation measurement mode in three different positions.
Analyses performed on the instrument:
- Low-field magnetic susceptibility
- Measurement of frequency dependence
- Measurement of anisotropy of magnetic susceptibility (AMS)
- Adapted for discrete centimetric samples of rocks, sediments, soils, archaeological baked clays…
Contacts:
Gwenaël Hervé : 01.69.08.02.48 / This email address is being protected from spambots. You need JavaScript enabled to view it.
Funding:
DIM-MAP ANIMAS project
Measurements of the palaeointensity of the geomagnetic field
Mobile furnace for paleointensity experiments (homemade equipment with Pyrox furnace)
Instrument description:
The device is designed in two parts: a mobile furnace (left side of the photo) and a fixed zone under a controlled magnetic field with a tube where the samples are located (right side of the photo). The sample holder in inconel can contain 48 standard-sized samples. Once at the desired temperature, the furnace is placed around the tube. Three independent heating zones ensure temperature uniformity. Depending on the temperature, the heating duration is 1 to 2 hours, after which the furnace is removed. The samples are then cooled by inertia or by air circulation along the tube.
The heating-cooling cycles are performed in air or under Argon flow continuously passing over the samples. The laboratory magnetic field, parallel to the tube axis, is maintained by a power supply with an accuracy of 0.1 µT and controlled throughout the experiment using a Foerster probe (model Magnetoscop 1.070 PFD-100).
Principle of analysis:
The device was specifically designed for Thellier-Thellier double-heating paleointensity protocols. Heating-cooling cycles can be performed with a magnetic field applied in two opposite directions or without field. The remanent magnetization of samples is measured after each cycle using the high-homogeneity cryogenic magnetometer. The possibility to perform heating-cooling cycles under Argon flow limits mineralogical changes in volcanic rocks during the protocol. The device also allows to correct paleointensities for the effects of anisotropy and cooling rate (slow cooling over approximately 6 hours).
Analyses performed on the instrument:
- Thellier-Thellier palaeointensity protocols
- On discrete standard-size specimens of volcanic rocks and archaeological baked clays.
Contacts:
Gwenaël Hervé : 01.69.08.02.48 / This email address is being protected from spambots. You need JavaScript enabled to view it.