Magnetic properties of nanoparticles fabricates via inert gas condensation. K. Coughlin, L. Zhai, R. Kraft, M.M. Patterson University of Wisconsin–Stout, Menomonie, WI Introduction The purpose of this research is to observe and study the effects of temperature variations on the formation of and magnetic properties of Iron/Platinum (FePt) nanoparticles. We hope to find properties that will suggest that FePt particles can be used for magnetic recording in computer storage devices or as a replacement to currently used rare earth metals. Background Exploration of the properties of alloys has existed since the first days of smelting iron in approximately 2500BC. Today, alloys are used in virtually every man made structure, electronics device, and tool manufactured. As those tools advance, we are able to study the properties of materials on a much smaller and smaller scale. When a material gets closer to the nanoscale, its properties can vary from accepted industry standards. When the number of atoms or molecules bonded together is so small that they occupy between 1 and 100 nanometers of space, the properties are no longer predictable. Colors displayed can change based on the amount of atoms present to reflect light. Due to the small mass of some particles, gravitational forces are negligible, giving way to electromagnetic forces that determine behavior. Figure 1. High-resolution transmission electron microscopy (HRTEM) image of a single FePt particle (photo M. Patterson) Figure 2. Example of sizes from nano to Nascar (picture from Apparatus (FePt Particle Synthesis) Argon gas is pumped into the bell jar vacuum chamber A voltage is applied to the FePt target plate Ar+ ions and electrons oscillate between two plates at high velocities Sputtering occurs when ions collide with FePt atoms on the target, knocking them off of the plate Aggregation (direct mutual attraction between particles) occurs when Liquid N₂ cools the plasma into clusters in the condensing region Figure 3. Bell Jar assembly diagram. Inset: our bell jar and test chamber being prepared for a test. Figure 4. diagram of equipment and lab set up Acknowledgements We gratefully acknowledge support from a UW-Stout Faculty Research Initiative SEED Grant; the NanoSTEM DIN; the UW-Stout Department of Physics; Shawn Kozey, Nate Hughes, Jacob Smith, Morgan Lowery, Mark Sala, Craig Hineline, Lucas Johnson, Ben Tredinnick, Ryan Schele and SPGNSFB References Principles of Plasma Discharges and Materials Processing, Michael A. Lieberman, Allan J. Lichtenberg - Wiley-Interscience (2005) MM Patterson, A Cochran, J Ferina, X Rui, TA Zimmerman, Z Sun, MJ Kramer, DJ Sellmyer, JE Shield, "Early stages of direct L10 FePt nanocluster formation: the effects of plasma characteristics", Journal of Vacuum Science and Technology B, Vol 28 (2), pp , March MM Patterson, X Rui, XZ Li, JE Shield, DJ Sellmyer, "Plasma ion heating produces L10 FePt nanoclusters", Materials Research Society Symposium Proceedings, 1087E (V08), In Progress Setup of equipment and fluid/gas routing systems Manufacturing of particles (nanomagnets) of various sizes Measurement of size (SEM, AFM) and magnetic characteristics (magnetometer). Exploring nano scale sized magnetic alternatives to rare earth alloys. Figure 5. Previous synthesis of FePt nanoparticles in N 2 plasma Power supply RF RF power Main power supply Rough Pump Collector Diffusion Pump Bell Jar and base Argon Gas Figure 6. SEM image of manufactured FePt particles