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Full-Text Articles in Physics

Temperature Dependence Of The Training Effect In Exchange Coupled Ferromagnetic Bilayers, Christian Binek, Srinivas Polisetty, Sarbeswar Sahoo Nov 2008

Temperature Dependence Of The Training Effect In Exchange Coupled Ferromagnetic Bilayers, Christian Binek, Srinivas Polisetty, Sarbeswar Sahoo

Christian Binek Publications

The temperature dependence of the training effect is studied in an exchange coupled thin-film bilayer composed of a hard ferromagnetic pinning (CoPtCrB) layer in proximity of a soft ferromagnetic pinned (CoCr) layer. Interlayer exchange shifts the hysteresis loops of the soft layer along the magnetic-field axis. This shift is quantified by the bias field in far reaching analogy to the exchange bias field of conventional antiferromagnetic/ferromagnetic heterostructures. A ferromagnetic domain state induced in the hard layer experiences aging very similar to the training behavior of the antiferromagnetic domain state in conventional exchange bias systems. Training originates from changes in ...


Quenching Of The Exchange Bias Training In Fe/Cr2o3/Fe Trilayer, Sarbeswar Sahoo, Christian Binek Oct 2008

Quenching Of The Exchange Bias Training In Fe/Cr2o3/Fe Trilayer, Sarbeswar Sahoo, Christian Binek

Christian Binek Publications

Exchange bias (EB) and its associated training effects are studied in an epitaxial Fe(10 nm)/Cr2O3(2.7 nm)/Fe(10 nm) trilayer heterostructure grown by molecular beam epitaxy. The EB decreases linearly with increasing temperature from T = 5 K to T = 50 K. It changes sign and becomes positive within 50 K < T < 200 K, finally changing back to regular EB for T<200K up to the highest measured temperature of T = 395 K. Remarkably, the latter is far above the bulk Néel temperature TN = 307 K. EB training effects occur only at 5 K < T < 50 K. We show that this training can be quenched by subjecting the system to DC magnetic field, µ0HDC <= 7 T. The applied field most likely induces a temperature dependent spin-flop transition. Upon its removal the antiferromagnetic Cr2O3 pinning layer evolves uniformly into its quasi-equilibrium spin configuration thus leading to quasi-equilibrium EB.


Electrically Controlled Magnetism, Christian Binek, Xi He, Yi Wang, Sarbeswar Sahoo Sep 2008

Electrically Controlled Magnetism, Christian Binek, Xi He, Yi Wang, Sarbeswar Sahoo

Christian Binek Publications

Manipulation of magnetically ordered states by electrical means is a promising approach towards novel spintronics devices. We report on the electric control of surface magnetism in Cr2O3 thin films and uniaxial anisotropy in ferroelectric/ferromagnetic heterostructures, respectively. Artificial magnetoelectricity is realized in a BaTiO3/Fe heterostructure. Here, thermally induced coercivity changes of the Fe hysteresis loop are used to derive the stress imposed by the ferroelectric BaTiO3 substrate on the adjacent Fe film. Electrically induced coercivity changes give rise to a giant magnetoelectric susceptibility in the vicinity of the magnetic coercive field.


Christian Binek: List Of Publications Jul 2008

Christian Binek: List Of Publications

Christian Binek Publications

Lists citations for 60 published articles and one monograph by Christian Binek of the Department of Physics and Astronomy at the University of Nebraska-Lincoln. Includes some links. Current as of July 2008.


Optimization Of Magneto-Optical Kerr Setup: Analyzing Experimental Assemblies Using Jones Matrix Formalism, Christian Binek May 2008

Optimization Of Magneto-Optical Kerr Setup: Analyzing Experimental Assemblies Using Jones Matrix Formalism, Christian Binek

Christian Binek Publications

We present a comparative study on an experimental and theoretical optimization of magneto-optical Kerr setups based on photoelastic modulation and phase sensitive detector methodology. The first and second harmonics, Iomega,2omega, of the reflected light intensity are measured for a CoO/Co magnetic reference film. The magnetic field dependence of the optical off-diagonal Fresnel reflection coefficients rps and rsp follows the sample magnetization. Different Kerr setups provide various dependencies of Iomega,2omega on the reflection coefficients and, hence, on the Kerr ellipticity epsilonK and rotation thetaK. Jones matrix formalism has been used to analyze the impact of a systematic variation ...


Temperature Dependence Of The Training Effect In Exchange Coupled Ferromagnetic Bilayers, Srinivas Polisetty, Sarbeswar Sahoo, Andreas Berger, Christian Binek Jan 2008

Temperature Dependence Of The Training Effect In Exchange Coupled Ferromagnetic Bilayers, Srinivas Polisetty, Sarbeswar Sahoo, Andreas Berger, Christian Binek

Christian Binek Publications

The temperature dependence of the training effect is studied in an exchange coupled thin-film bilayer composed of a hard ferromagnetic pinning (CoPtCrB) layer in proximity of a soft ferromagnetic pinned (CoCr) layer. Interlayer exchange shifts the hysteresis loops of the soft layer along the magnetic-field axis. This shift is quantified by the bias field in far reaching analogy to the exchange bias field of conventional antiferromagnetic/ferromagnetic heterostructures. A ferromagnetic domain state induced in the hard layer experiences aging very similar to the training behavior of the antiferromagnetic domain state in conventional exchange bias systems. Training originates from changes in ...