Some magnetic materials, such as nanowires, nanoparticles, and thin films, typically possess weak magnetic moments. This is due mainly to the small amount of magnetic material present. Therefore, when you need to characterize the small magnetic moment of such materials – and obtain an acceptable signal-to-noise ratio in the measurement – the sensitivity of your instrumentation is key.
In this new application note, we examine the utility and highly sensitive measurement capabilities of our 8600 Series VSM for characterizing low-moment materials at ambient temperatures. We present major hysteresis loop (MHL) and first-order reversal curve (FORC) measurement results for a 5.8 μemu (5.8 × 10-9 Am2) cobalt-platinum (CoPt) thin-film sample and MHL results for 1.5 μemu (1.5 × 10-9 Am2) and 600 nemu (6 × 10-10 Am2) iron-doped (0.5%) silicon nitride (SiN) ceramic sphere samples.
Obtaining the hysteresis loop measurements of the Fe-doped SiN sample with a saturation moment of only 600 nemu is most notable.
FORC measurements provide information that cannot be obtained from a hysteresis loop measurement alone, such as information relating to magnetic interactions and coercivity distributions. The 8600 Series VSM has been specifically designed to execute FORC measurements quickly and easily, and with high precision. With its very low noise floor, the VSM doesn’t require long signal averages to obtain good signal-to-noise — even for low-moment samples — which equates to shorter FORC measurement times.
Particularly interested in FORC measurements?
FORC Workshop in June
Lake Shore Cryotronics is proud to sponsor an upcoming FORC Workshop to be held Monday, June 5, in conjunction with the 13th IRM Conference on Rack Magnetism at the Univ. of Minnesota. This in-depth workshop will include presentations from leaders in the field of FORC, covering the basics of FORC theory, how FORCs are applied in rock magnetism, and basic to advanced measurement strategies, such as induced/transient/remanence FORC measurements, FORC processing methods, and advanced analysis methods, such as FORC PCA. Novel applications of FORC will also be touched on. For more information, visit the workshop website.
This is the third time Lake Shore has sponsored the workshop, the last time being in 2016 when held before the start of the 61st Annual Conference on Magnetism and Magnetic Materials (MMM) in New Orleans.
Recently published FORC-related papers
For recent examples of how our 8600 Series VSM has been used for research, read:
- “Rotation of a Ferromanganese Nodule in the Penrhyn Basin, South Pacific, Tracked by the Earth's Magnetic Field,” an AGU paper that references the use of our Model 8604 for isothermal remanent magnetization (IRM) FORC analysis of 10 magnetic mineral specimens.
- “Factors Controlling the Early-Mid Holocene Aeolian Sediment Accumulation in the Pum Qu Catchment and Environmental Implications for the Southern Tibetan Plateau,” a Quaternary International paper (subscription required) describing the use of our system for obtaining hysteresis, FORC diagrams, and IRM acquisition curves to aid in identifying species and grain sizes of magnetic minerals.
- “Influence of Seasonal Post-Depositional Processes on the Remanent Magnetization in Varved Sediments from Glacial Lake Ojibway (Canada),” an AGU paper referencing the use of our VSM for high-resolution FORC measurements in order to obtain information relating to natural remanent magnetization (NRM).
- “Understanding Magnetic Interactions and Reversal Mechanisms in a Spinodally Decomposed Cobalt Ferrite Using First Order Reversal Curves,” an AIP Advances paper co-authored by Lake Shore's Brad Dodrill describing how our VSM aided in FORC analysis of a unique class of nanostructured ferrites.