Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 5: Micro- and Nanostructured Magnetic Materials I
MA 5.7: Vortrag
Montag, 22. März 2010, 12:30–12:45, H23
Magnetization dynamics of a CrO2 grain studied by micro-Hall magnetometry — •Pintu Das1,2, Jens Müller1,2, Ashna Bajpai3, Fabrizio Porrati2, Franziska Wolny3, Steffen Wirth1, Thomas Mühl3, Michael Huth2, Rüdiger Klingeler3, and Bernd Büchner3 — 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, Dresden, — 2Instiute of Physics, Goethe University, Max von Laue Str. 1, Frankfurt am Main — 3Instiute for Solid State and Materials Research, Helmholtz Str. 20, Dresden
In the field of magnetism, it is often difficult to gain a complete quantitative understanding of magnetization dynamics in bulk or multigrain systems. Studying the magnetic behaviour of single magnetic entities is thus very important in order to understand the process of magnetization reversal in complex magnetic materials. In this work, we have studied the magnetization reversal of a single CrO2 grain of size ∼ 8 × 2 × 2 µ m3 using micro-Hall magnetometry technique. CrO2 is ferromagnetic and has a Tc of ∼ 393 K. The grain has an antiferromagnetic Cr2O3 layer of thickness ∼ 2-5 nm. We observe that the magnetization in this grain switches through a series of Barkhausen jumps of stochastic nature. In the temperature range of 5 K - 60 K, simultaneously measured magnetization at both ends (along the long axis) of the grain show that these jumps are correlated. The data may allow us to infer the nature of the magnetic domains inside the grain and the behaviour of the domain walls for externally applied magnetic fields. We discuss the results and compare them with micro-magnetic simulations for the magnetic behaviour of this sample.