Berlin 2012 – scientific programme

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KR: Fachgruppe Kristallographie

KR 5: Poster I – including Multiferroics (MA with DF, DS, KR, TT)

KR 5.54: Poster

Tuesday, March 27, 2012, 12:15–15:15, Poster A

Perpendicular exchange bias in ferrimagnetic spin valves — •Radu Abrudan¹, Ilie Radu², Detlef Schmitz³, Hartmut Zabel¹, and Florin Radu³ — ¹Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany — ²Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen,The Netherlands — ³Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany

Exchange bias effect refers to the shift of the hysteresis loop of a ferromagnet which is in direct contact to an antiferromagnet. For applications in spintronics a robust and tunable EB effect is required. We present experimental evidence for perpendicular EB in ferrimagnetic spin valves in a DyCo₅/Ta/Fe₇₆Gd₂₄ prototype trilayer, where the DyCo₅ alloy plays the role of a hard ferrimagnet and the Fe₇6Gd₂₄ is a soft ferrimagnet. Taking advantage of the tunability of the exchange coupling between the ferrimagnetic layers by means of thickness variation of an interlayer spacer, we show that perpendicular exchange bias can be induced with desirable absolute values at room temperature with no field cooling procedure. Moreover, the shift of the hysteresis loop can be reversed with relatively low magnetic fields of several hundred Oersteds. This flexibility in controlling a robust perpendicular EB at room temperature may be of crucial importance for applications.