Regensburg 2010 – wissenschaftliches Programm

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KR: Fachverband Kristallographie

KR 10: Poster: Multiferroics (with MA, DF, KR, DS)

KR 10.15: Poster

Dienstag, 23. März 2010, 10:45–13:45, Poster A

Angle-dependent magnetotransport in Nickel thin films — •M. Althammer, M. Wagner, A. Brandlmaier, M. Weiler, S. Geprägs, R. Gross, and S.T.B. Goennenwein — Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany

Angle-dependent magnetoresistance (ADMR) measurements have proven to be a powerful tool to investigate magnetic anisotropy in ferromagnetic thin films [1]. We here apply the ADMR technique to polycrystalline Nickel thin films deposited via electron beam evaporation onto LiNbO₃, MgO and BaTiO₃ substrates. The 50 nm thick films were patterned into Hall-bar structures with optical lithography and etching or lift-off. In the ADMR measurements, the longitudinal and transverse resistance is recorded as a function of the orientation of the external magnetic field at constant field strength. In all samples investigated the strain in the Nickel thin film can be tuned in situ, either via temperature or an applied electric field. Due to magnetoelastic coupling the strain leads to a change in the magnetic anisotropy. We can quantitatively explain our data with basic magnetoelastic coupling theory, taking into account the thermal dependence of the lattice parameters of the respective substrate. Fitting the data by a single domain model allows to extract the magnetic anisotropy. We also discuss the external magnetic field and temperature dependence of the resistivity parameters. Financial Support by the DFG (SPP 1157 and GO 944/3) is gratefully acknowledged.

[1] W. Limmer et al., PRB 74, 205205 (2006)