DC - AC MM / DC – AC Magnetic Measurements
Magnetic measurements are used to characterize an important category of materials where the spin of the atoms controls their response to an external magnetic field. This category of materials includes ferromagnets, ferrimagnets, antiferromagnets, paramagnets, and molecular based magnetic materials. Magnetic measurements are needed for the understanding of nanoscale particles and the study of diverse quantum materials, including superconductors and their devices. With magnetic measurements, the majority of the physical properties which characterize magnetic or superconducting materials can be quantitatively evaluated. Representative examples include:
(a) The magnetization curve (magnetic moment vs external magnetic field).
(b) The temperature which marks the transition from ferromagnetic, antiferromagnetic, superconducting state to the paramagnetic, normal state.
(c) The saturation and remanence magnetization, the coercive magnetic field for ferromagnetic materials.
(d) All the characteristic magnetic fields for a type I and type II superconductors.
(e) The effective magnetic moment for a paramagnetic material.
(f) The superparamagnetic dynamics and the blocking temperature of magnetic nanoparticles.
DC Magnetometer & AC Susceptometer based on Quantum Design Physical Property Measurement System (PPMS)
Characterization of the physical properties (magnetization curve, transition temperature from ferromagnetic / antiferromagnetic / superconducting state to the paramagnetic, normal state, saturation and remanence magnetization etc.) of magnetic/superconducting materials
The PPMS is an open-architecture, variable-temperature field system, optimized, to perform a variety of automated magnetic measurements. This system is equipped with ac-susceptibility and magnetic moment extraction options. Samples can be measured in bulk and powder form (maximum dimensions for a cylindrical sample: diameter up to 8 mm, height up to 10 mm):
(a) dc magnetic moment and magnetic ac susceptibility (10-10 kHz) measurements at temperatures in the range of 2-300 K
(b) dc magnetic field in the range of 0-9 Tesla
Dr. Michael Pissas ( m.pissas@inn.demokritos.gr )
DC Magnetometer & AC Susceptometer, based on a MagLab-EXA 2000 multi-measurement system (Oxford Instruments)
Automated physical property materials characterisation (e.g. measuring moment versus applied magnetic field or moment versus temperature) for deciphering static and dynamic phenomena, associated with superconductivity, or the Curie, Néel and blocking temperatures of ferromagnetic, antiferromagnetic, and superparamagnetic phases.
(a) High magnetic field (H= 0-7 Tesla), (b) Low-temperature liquid Helium cryostat (T= 1.8-350 K), (c) DC moment extraction (10-4 emu), (d) AC susceptibility (~10-6 emu), f= 0.01-10 kHz, (e) samples in diverse morphologies, ranging from films and nanocrystals to bulk forms – typical container, gelatin capsule ~15 mm long, with O.D. 5 mm. The software measurement sequencer (open source) provides a set of high level actions to enable you to write and control measurements in a way that suit your own specific requirements.
Dr. Alexandros Lappas (lappas@iesl.forth.gr)
