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Graham Kimbell

Research Interests

Superconducting spintronics

I am creating epitaxial oxide heterostructures using pulsed laser deposition in order to investigate triplet superconductivity.

The conversion from singlet to triplet Cooper pairs has been shown to occur when pairs experience a magnetic inhomogeneity1. In the SRO113/LSMO system, a magnetic non-collinearity has been shown to form in the SRO due to a competition between magnetocrystalline anisotropy and antiferromagnetic interfacial exchange coupling2, and triplet currents have been reported in YBCO/SRO/LSMO/Au/Nb mesa-structures3. However, conflicting studies have shown evidence4 or lack thereof5 for a 'spin active' YBCO/LSMO interface in which triplet conversion can take place without any mixing layer.

I will compare the efficiency of triplet conversion by growing unpatterned triplet spin valves and nanopillar Josephson junctions of YBCO/LSMO with and without spin mixing SRO layers.

[1]   F. S. Bergeret et al., Phys. Rev. Lett. 86, 4096 (2001).
[2]   X. Ke et al., Phys. Rev. Lett. 110, 237201 (2013).
[3]   Y. N. Khaydukov et al., Phys. Rev. B 90, 035130 (2014).
[4]   C. Visani et al., Nat. Phys. 8, nphys2318 (2012).
[5]   A. M. Petrzhik et al., J. Exp. Theor. Phys. 112, 1042 (2011).