Imaging magnetic dynamics with heat
Speaker: Isaiah Gray (Cornell University)
Imaging magnetic dynamics with heat Abstract:
Magnetic microscopy is fundamental to new discoveries in spintronics, both as a science and as an emerging technology. However, there are few existing tabletop techniques to image magnetic dynamics at their characteristic sub-micron length scales and picosecond time scales simultaneously. In this talk I introduce a new kind of magnetic microscope, dubbed TRANE (Time-Resolved Anomalous Nernst Effect). We generate short-lived thermal gradients with a focused pulsed laser, exploiting spin-magnetothermal effects that induce a voltage which reports the local magnetic moment. We generate ferromagnetic resonance (FMR) with RF current and demonstrate the first spatially-resolved FMR images in CoFeB devices and Pt/CoFeB spin Hall multilayers, showing significant variation in resonance phase and amplitude. Using the spin Seebeck effect we extend our technique to magnetic insulators, choosing yttrium iron garnet (YIG), and show multiple FMR modes coexisting in a single Pt/YIG device. I describe a new application of TRANE to image the antiferromagnet FeRh, using the phase transition to ferromagnet at ~100 \deg C to control the antiferromagnetic order. Finally, I discuss recent work extending TRANE with thermal scan-probe microscopy, a development which would enable truly nanoscale imaging of magnetic dynamics.
Date: April 7, 2017 (Friday) Time: Lunch at 12:00 pm Talk begins at 12:15 pm Place: Phillips 233 Sponsored by: School of ECE, Cornell University and partially funded by GPSAFC Open to all students, faculty, and staff.
To Learn More: https://orgsync.rso.cornell.edu/org/eds
Biography: Isaiah Gray is a PhD student in Prof. Gregory Fuchs's lab in the Applied Physics department at Cornell. He received a B.S. in Physics from the University of Minnesota Twin Cities in 2014. His research uses novel magnetic microscopy methods to image materials difficult to study in other ways, focusing on antiferromagnets. He received the Watt W. Webb Graduate Fellowship in Nanoscience in 2015.
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Imaging magnetic dynamics with heat Abstract:
Magnetic microscopy is fundamental to new discoveries in spintronics, both as a science and as an emerging technology. However, there are few existing tabletop techniques to image magnetic dynamics at their characteristic sub-micron length scales and picosecond time scales simultaneously. In this talk I introduce a new kind of magnetic microscope, dubbed TRANE (Time-Resolved Anomalous Nernst Effect). We generate short-lived thermal gradients with a focused pulsed laser, exploiting spin-magnetothermal effects that induce a voltage which reports the local magnetic moment. We generate ferromagnetic resonance (FMR) with RF current and demonstrate the first spatially-resolved FMR images in CoFeB devices and Pt/CoFeB spin Hall multilayers, showing significant variation in resonance phase and amplitude. Using the spin Seebeck effect we extend our technique to magnetic insulators, choosing yttrium iron garnet (YIG), and show multiple FMR modes coexisting in a single Pt/YIG device. I describe a new application of TRANE to image the antiferromagnet FeRh, using the phase transition to ferromagnet at ~100 \deg C to control the antiferromagnetic order. Finally, I discuss recent work extending TRANE with thermal scan-probe microscopy, a development which would enable truly nanoscale imaging of magnetic dynamics.
Date: April 7, 2017 (Friday) Time: Lunch at 12:00 pm Talk begins at 12:15 pm Place: Phillips 233 Sponsored by: School of ECE, Cornell University and partially funded by GPSAFC Open to all students, faculty, and staff.
To Learn More: https://orgsync.rso.cornell.edu/org/eds
Biography: Isaiah Gray is a PhD student in Prof. Gregory Fuchs's lab in the Applied Physics department at Cornell. He received a B.S. in Physics from the University of Minnesota Twin Cities in 2014. His research uses novel magnetic microscopy methods to image materials difficult to study in other ways, focusing on antiferromagnets. He received the Watt W. Webb Graduate Fellowship in Nanoscience in 2015.
To join the mailing list, send an email to [email protected] with no subject and type in “join” (without quotes) as the body of your message.
