Understanding interlayer coupling and buried interfacial magnetism using polarized neutron reflectometry

Patrick Quarterman

NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States

Polarized neutron reflectometry (PNR) is a powerful characterization method for understanding magnetic thin film materials since it provides direct and simultaneous measurement of chemical composition and in-plane magnetization, as a function of depth with sub-nanometer resolution. This makes the technique uniquely suited for probing buried interfacial magnetism and magnetic interlayer coupling in thin films. Magnetic insulators and metals are widely used in spintronic structures for control of magnetoresistance states and magnon currents. Conventional spintronic structures are primarily based on either metallic or insulating magnetic materials. However, heterostructures containing both materials present many remaining questions, while having potential to exhibit novel magnetic coupling and magnon transport properties. I will show how model-fitting data collected on magnetic insulator/metal heterostructures has led to the recent discovery of novel antiferromagnetic coupling between yttrium iron garnet (YIG) and permalloy (Py, Ni80Fe20) when grown on Si [1].  In this tutorial, I will demonstrate reduction and model-fitting of PNR data using the REDUCTUS package and REFL1D program [2,3].

[1] Fan and Quarterman et al: arXiv:2002.08266
[2] B. Maranville, W. Ratfliff II, and P. Kienzle J. Appl. Cryst. 51, 1500-1506 (2018)
[3] P.A. Kienzle, B.B. Maranville, K.V. O'Donovan, J.F. Ankner, N.F. Berk, C.F. Majkrzak; https://www.nist.gov/ncnr/reflectometry-software 2017-