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Christian Binek Publications

2011

Articles 1 - 4 of 4

Full-Text Articles in Physics

Magnetic Entropy Changes In Nanogranular Fe:Ni61Cu39, Steven A. Michalski, Ralph A. Skomski, Tathagata Mukherjee, Xingzhong Li, Christian Binek, David J. Sellmyer Apr 2011

Magnetic Entropy Changes In Nanogranular Fe:Ni61Cu39, Steven A. Michalski, Ralph A. Skomski, Tathagata Mukherjee, Xingzhong Li, Christian Binek, David J. Sellmyer

Christian Binek Publications

Artificial environment-friendly Gd-free magnetic nanostructures for magnetic cooling are investigated by temperature-dependent magnetic measurements. We consider two-phase nanocomposites where nanoclusters (Fe) are embedded in a Ni61Cu39 matrix. Several composite films are produced by cluster deposition. The average Fe cluster size depends on the deposition conditions and can be tuned by varying the deposition conditions. The quasiequilibrium Curie temperature of the Fe particles is high, but slightly lower than that of bulk Fe due to finite-size effects. Our experiments have focused on ensembles of 7.7 nm Fe clusters in a matrix with a composition close to Ni ...


When Measured Spin Polarization Is Not Spin Polarization, Peter A. Dowben, Ning Wu, Christian Binek Apr 2011

When Measured Spin Polarization Is Not Spin Polarization, Peter A. Dowben, Ning Wu, Christian Binek

Christian Binek Publications

Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO2 and Cr2O3 illustrate some of the complications which hinders comparisons of spin polarization values.


Imaging And Control Of Surface Magnetization Domains In A Magnetoelectric Antiferromagnet, Ning Wu, Xi He, Aleksander L. Wysocki, Uday Lanke, Takashi Komesu, Kirill D. Belashchenko, Christian Binek, Peter A. Dowben Feb 2011

Imaging And Control Of Surface Magnetization Domains In A Magnetoelectric Antiferromagnet, Ning Wu, Xi He, Aleksander L. Wysocki, Uday Lanke, Takashi Komesu, Kirill D. Belashchenko, Christian Binek, Peter A. Dowben

Christian Binek Publications

We report the direct observation of surface magnetization domains of the magnetoelectric Cr2O3 using photoemission electron microscopy with magnetic circular dichroism contrast and magnetic force microscopy. The domain pattern is strongly affected by the applied electric field conditions. Zero-field cooling results in an equal representation of the two domain types, while electric-field cooling selects one dominant domain type. These observations confirm the existence of surface magnetization, required by symmetry in magnetoelectric antiferromagnets.


Magnetometry And Transport Data Complement Polarized Neutron Reflectometry In Magnetic Depth Profiling, Yi Wang, Xi He, Tathagata Mukherjee, Mary Lee Fitzsimmons, Sarbeswar Sahoo, Christian Binek Jan 2011

Magnetometry And Transport Data Complement Polarized Neutron Reflectometry In Magnetic Depth Profiling, Yi Wang, Xi He, Tathagata Mukherjee, Mary Lee Fitzsimmons, Sarbeswar Sahoo, Christian Binek

Christian Binek Publications

Exchange coupled magnetic hard layer/soft layer thin films show a variety of complex magnetization reversal mechanisms depending on the hierarchy of interaction strengths within and between the films. Magnetization reversal can include uniform rotation, soft layer biasing, as well as exchange spring behavior. We investigate the magnetization reversal of a CoPt/Permalloy/Ta/Permalloy heterostructure. Here, Stoner-Wohlfarth-type uniform magnetization rotation of the virtually free Permalloy layer and exchange spring behavior of the strongly pinned Permalloy layer are found in the same sample. We investigate the complex magnetization reversal by polarized neutron reflectometry, magnetometry, and magneto-transport. The synergy of combining ...