All Publications

  • Understanding Signatures of Emergent Magnetism in Topological Insulator/Ferrite Bilayers. Physical review letters Riddiford, L. J., Grutter, A. J., Pillsbury, T., Stanley, M., Reifsnyder Hickey, D., Li, P., Alem, N., Samarth, N., Suzuki, Y. 2022; 128 (12): 126802


    Magnetic insulator-topological insulator heterostructures have been studied in search of chiral edge states via proximity induced magnetism in the topological insulator, but these states have been elusive. We identified MgAl_{0.5}Fe_{1.5}O_{4}/Bi_{2}Se_{3} bilayers for a possible magnetic proximity effect. Electrical transport and polarized neutron reflectometry suggest a proximity effect, but structural data indicate a disordered interface as the origin of the magnetic response. Our results provide a strategy via correlation of microstructure with magnetic data to confirm a magnetic proximity effect.

    View details for DOI 10.1103/PhysRevLett.128.126802

    View details for PubMedID 35394317

  • Anisotropic Magnon Spin Transport in Ultrathin Spinel Ferrite Thin Films─Evidence for Anisotropy in Exchange Stiffness. Nano letters Li, R., Li, P., Yi, D., Riddiford, L. J., Chai, Y., Suzuki, Y., Ralph, D. C., Nan, T. 1800


    Magnon-mediated spin flow in magnetically ordered insulators enables long-distance spin-based information transport with low dissipation. In the materials studied to date, no anisotropy has been observed in the magnon propagation length as a function of propagation direction. Here, we report measurements of magnon spin transport in a spinel ferrite, magnesium aluminum ferrite MgAl0.5Fe1.5O4 (MAFO), which has a substantial in-plane 4-fold magnetic anisotropy. We observe spin diffusion lengths > 0.8 mum at room temperature in 6 nm films, with spin diffusion lengths 30% longer along the easy axes compared to the hard axes. The sign of this difference is opposite to the effects just of anisotropy in the magnetic energy for a uniform magnetic state. We suggest instead that accounting for anisotropy in exchange stiffness is necessary to explain these results. These findings provide an approach for controlling magnon transport via strain, which opens new opportunities for designing magnonic devices.

    View details for DOI 10.1021/acs.nanolett.1c04332

    View details for PubMedID 35077185

  • Charge-spin interconversion in epitaxial Pt probed by spin-orbit torques in a magnetic insulator PHYSICAL REVIEW MATERIALS Li, P., Riddiford, L. J., Bi, C., Wisser, J. J., Sun, X., Vailionis, A., Veit, M. J., Altman, A., Li, X., Mahendra, D. C., Wang, S. X., Suzuki, Y., Emori, S. 2021; 5 (6)
  • Emergent long-range magnetic order in ultrathin (111)-oriented LaNiO3 films NPJ QUANTUM MATERIALS Kane, M. M., Vailionis, A., Riddiford, L. J., Mehta, A., N'Diaye, A. T., Klewe, C., Shafer, P., Arenholz, E., Suzuki, Y. 2021; 6 (1)
  • Ultra-low magnetic damping in epitaxial Li0.5Fe2.5O4 thin films APPLIED PHYSICS LETTERS Zheng, X., Riddiford, L. J., Wisser, J. J., Emori, S., Suzuki, Y. 2020; 117 (9)

    View details for DOI 10.1063/5.0023077

    View details for Web of Science ID 000570143100001

  • The role of iron in magnetic damping of Mg(Al,Fe)(2)O-4 spinel ferrite thin films APPLIED PHYSICS LETTERS Wisser, J. J., Riddiford, L. J., Altman, A., Li, P., Emori, S., Shafer, P., Klewe, C., NDiaye, A. T., Arenholz, E., Suzuki, Y. 2020; 116 (14)

    View details for DOI 10.1063/5.0003628

    View details for Web of Science ID 000526869500001

  • Ultrathin interfacial layer with suppressed room temperature magnetization in magnesium aluminum ferrite thin films APPLIED PHYSICS LETTERS Wisser, J. J., Emori, S., Riddiford, L., Altman, A., Li, P., Mahalingam, K., Urwin, B. T., Howe, B. M., Page, M. R., Grutter, A. J., Kirby, B. J., Suzuki, Y. 2019; 115 (13)

    View details for DOI 10.1063/1.5111326

    View details for Web of Science ID 000487997400005

  • Efficient spin current generation in low-damping Mg(Al, Fe)(2)O-4 thin films APPLIED PHYSICS LETTERS Riddiford, L. J., Wisser, J. J., Emori, S., Li, P., Roy, D., Cogulu, E., van't Erve, O., Deng, Y., Wang, S. X., Jonker, B. T., Kent, A. D., Suzuki, Y. 2019; 115 (12)

    View details for DOI 10.1063/1.5119726

    View details for Web of Science ID 000487038900007