Probing non-collinear magnetic states using thermal gradients
| Date/Time: | Thursday, 16 Nov 2017 from 11:00 am to 11:50 am |
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| Location: | Physics 18/19 |
| Phone: | 515-294-7377 |
| Channel: | College of Liberal Arts and Sciences |
| Actions: | Download iCal/vCal | Email Reminder |
The spin-Seebeck effect in ferromagnetic insulators has been widely studied in recent years in the context of spintronics. In essence, a thermal gradient across a magnetic material drives excitations that carry spin, which may then be detected electrically, telling us about the nature of the underlying magnetic order. We have developed a technique that allows us to measure these effects in patterned structures on the micron scale. I will discuss how we have used this approach to probe magnetic interactions in a variety of materials with non-collinear spin structures. In particular, I will discuss the spin-Seebeck effect in a geometrically frustrated classical spin liquid [1], and also in an antiferromagnetic insulator with uniaxial anisotropy where the spectrum of magnetic excitations is gapped [2]. Lastly, I will discuss how we characterize non-collinear magnetism in patterned wires of an MBE grown superlattice of La2/3Sr1/3MnO3 (LSMO) and LaNiO3 (LNO), [3] using a combination of the anomalous Nernst effect and anisotropic magnetoresistance measurements. In all of these examples, we are able to extract detailed information about the magnetic structure from a mesoscopic volume, which opens up possibilities for many materials systems which may not be easily probed by other means.
[1] S. M. Wu, et al., "Antiferromagnetic spin Seebeck effect" Phys. Rev. Lett. 116,097204 (2016)
[2] S. M. Wu, et al., "Paramagnetic spin Seebeck effect", Phys. Rev. Lett. 114,186602 (2015)
[3] J. Hoffman et al., "Oscillatory Non-collinear Magnetism Induced by Interfacial Charge Transfer in Metallic Oxide Superlattices" Phys. Rev. X. 6, 041038 (2016).