Resonant nanodiffraction x-ray imaging reveals role of magnetic domains in complex oxide spin caloritronics

Paul G Evans; Samuel D Marks; Stephan Geprägs; Maxim Dietlein; Yves Joly; Minyi Dai; Jiamian Hu; Laurence Bouchenoire; Paul B J Thompson; Tobias U Schülli; Marie-Ingrid Richard; Rudolf Gross; Dina Carbone; Danny Mannix

doi:10.1126/sciadv.aba9351

Resonant nanodiffraction x-ray imaging reveals role of magnetic domains in complex oxide spin caloritronics

Sci Adv. 2020 Oct 2;6(40):eaba9351. doi: 10.1126/sciadv.aba9351. Print 2020 Oct.

Authors

Paul G Evans¹, Samuel D Marks², Stephan Geprägs³, Maxim Dietlein^{3

4}, Yves Joly⁵, Minyi Dai², Jiamian Hu², Laurence Bouchenoire^{6

7}, Paul B J Thompson^{6

7}, Tobias U Schülli⁸, Marie-Ingrid Richard^{8

9}, Rudolf Gross^{3

4

10}, Dina Carbone¹¹, Danny Mannix^{5

12

13}

Affiliations

¹ University of Wisconsin-Madison, Madison, WI 53706, USA. pgevans@wisc.edu.
² University of Wisconsin-Madison, Madison, WI 53706, USA.
³ Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany.
⁴ Physik-Department, Technische Universität München, 85748 Garching, Germany.
⁵ Université Grenoble Alpes, CNRS, Institut Néel, 38042 Grenoble, France.
⁶ XMaS, ESRF, The European Synchrotron, 38043 Grenoble, France.
⁷ University of Liverpool, Department of Physics, Liverpool L69 3BX, UK.
⁸ ESRF, The European Synchrotron, 38043 Grenoble, France.
⁹ Aix Marseille Université, CNRS, IM2NP UMR 7334, Université de Toulon, Marseille 13397, France.
¹⁰ Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 7, 80799 München, Germany.
¹¹ MAX IV Laboratory, Fotongatan 2, 224 84 Lund, Sweden.
¹² European Spallation Source, SE-221 00 Lund, Sweden.
¹³ Aarhus University, Langelandsgade 140, DK-8000 Aarhus, Denmark.

Abstract

Spin electronic devices based on crystalline oxide layers with nanoscale thicknesses involve complex structural and magnetic phenomena, including magnetic domains and the coupling of the magnetism to elastic and plastic crystallographic distortion. The magnetism of buried nanoscale layers has a substantial impact on spincaloritronic devices incorporating garnets and other oxides exhibiting the spin Seebeck effect (SSE). Synchrotron hard x-ray nanobeam diffraction techniques combine structural, elemental, and magnetic sensitivity and allow the magnetic domain configuration and structural distortion to be probed in buried layers simultaneously. Resonant scattering at the Gd L₂ edge of Gd₃Fe₅O₁₂ layers yields magnetic contrast with both linear and circular incident x-ray polarization. Domain patterns facet to form low-energy domain wall orientations but also are coupled to elastic features linked to epitaxial growth. Nanobeam magnetic diffraction images reveal diverse magnetic microstructure within emerging SSE materials and a strong coupling of the magnetism to crystallographic distortion.

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