[16p-S2_201-1~11] 10.4 Spintronics in semiconductor, topological material, superconductor, and multiferroics

4:45 PM - 5:00 PM JST(7:45 AM - 8:00 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation AwardEnglish Presentation

[16p-S2_201-11] Intrinsic low-spin state and strain-tunable anomalous Hall scaling in high-quality SrRuO₃ (111) films

〇Harunori Shiratani^1,2, Yuki K Wakabayashi¹, Yoshiharu Krockenberger¹, Masaki Kobayashi¹, Kohei Yamagami³, Takahito Takeda², Shinobu Ohya^2,4, Masaaki Tanaka^2,4, Yoshitaka Taniyasu¹ (1.NTT-BRL, 2.Univ. of Tokyo, 3.JASRI, 4.CSRN Univ. of Tokyo)

Keywords:

Weyl semimetal,perovskite oxide,SrRuO3

SrRuO₃ (SRO) is a 4d transition-metal oxide perovskite that has been extensively studied as a prototypical itinerant ferromagnet with intermediate electron correlation and large magnetocrystalline anisotropy and as a magnetic Weyl semimetal. Moreover, there have been reports of a strain-induced high-spin state (4 μ_B per Ru⁴⁺) on the SRO (111) films, prompting a long-standing debate over its existence. In this study, we grew high-quality SRO (111) films with thicknesses t = 1.2–60 nm on SrTiO₃ (111) by machine-learning-assisted molecular beam epitaxy and characterized their structure, magnetism, and magnetotransport property. HRXRD-RSM and cross-sectional STEM confirmed epitaxy with in-plane coherent compressive strain for t = 10 and 20 nm, and strain relaxation at t = 60 nm. The coherently strained film with t = 20 nm was grown epitaxially with an abrupt substrate/film interface. The 60-nm-thick film reached a residual resistivity ratio of 45.5, the highest value reported for SRO (111) films. We observed robust, non-saturating linear positive magnetoresistance up to 14 T and analyzed the anomalous Hall effect (AHE) by scaling to separate intrinsic and extrinsic contributions. Comparison between coherently strained (t = 10, 20 nm) and relaxed (t = 60 nm) films shows that (111) epitaxial strain systematically tunes the relative weight of the AHE mechanisms. SQUID magnetometry together with Ru M_2,3 and O K-edge soft X-ray absorption spectroscopy /X-ray magnetic circular dichroism and sum-rule analysis indicated an intrinsically low-spin Ru ground state for both coherently strained and relaxed films; Both coherently strained and relaxed films have a magnetic moment below 1.5 /Ru. These results position SRO (111) as a materials platform for (111)-oriented oxide heterostructures and spin-topological devices.