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TT: Fachverband Tiefe Temperaturen

TT 66: Poster Session Transport

TT 66.5: Poster

Donnerstag, 19. März 2020, 15:00–19:00, P2/EG

Noise and transport measurements in atomic contacts of rare-earth and transition metals — •Marcel Strohmeier, Martin Prestel, and Elke Scheer — Department of Physics, University of Konstanz, 78457 Konstanz, Germany

We study the formation of atomic-scale magnetic ordering in rare-earth and transition metals. For Gd, a well-known Heisenberg ferromagnet with localized 4f electrons, theoretical studies predict a spin-polarized (SP) transport behavior in reduced dimensions [1]. Otherwise there are paramagnetic materials like Pd or Ir, where an emerging magnetic ordering in small dimension is expected due to the Stoner instability [2, 3]. Nonmonotonic magnetotransport has been reported for atomic contacts of Pt [4], Pd [5], and Ir [6]. Here, we extend the investigations by measurements of the shot noise. Shot noise allows insights into the channel configuration [7] and is sensitive to SP [8]. We study atomic contacts of Gd, Ir, Pd, Pt, and Co using the mechanically controllable break junction (MCBJ) technique at low temperatures. While no evidence for SP is observed for Pt and Pd, we find clear deviation from the usual shot-noise behavior for Gd and Ir.

[1] Olivera et al., PRB 95, 075409 (2017)

[2] Delin et al., PRL 92, 057201 (2004)

[3] Delin et al., PRB 68, 144434 (2003)

[4] Strigl et al., Nat. Comm. 6, 6172 (2015)

[5] Strigl et al., PRB 94, 144431 (2016)

[6] Prestel et al., PRB, accepted

[7] Kumar et al., PRL 108, 146602 (2012)

[8] Burtzlaff et al., PRL 114, 016602 (2015)