SEMPA topographic (a), in-plane [(b), (d), and (e)] and out-of-plane (c) polarization images of a Co STM tip. The black-and-white contrast in the in-plane polarization images corresponds to left and right magnetization. The gray areas are either magnetized perpendicular to the tip axis or have no remanent magnetization. Image (b) shows the magnetization of the tip after heating in UHV, (d) after applying an external field of 750 Oe along the tip axis, and (e) after the reversal of the applied field. The corresponding out-of-plane polarization image (c) shows no contrast. All images are measured in remanence.
SEMPA topographic (a) and in-plane (b) polarization image of the apex of a Co STM tip.
In-axis component of the stray field of a ferromagnetic tip calculated as a function of the distance to the tip axis. The tip is assumed to have an alternating domain pattern along the axis (a). All regions are assumed to be magnetized to the same value of 18.2 kOe, but with magnetization directions of the apex D1 and D3 parallel and D2 and D4 antiparallel to the tip axis. The contributions to the total stray field of the individual domains (dashed curves) and the overall sum (solid curve) are shown (b). Note that the values for the curves of D2 and D4 are negative and that negative values in the graph for the apex are not shown. (c) shows the calculation for different values of the tip’s apex radius.
-wide SEMPA out-of-plane polarization image of 2-ML-thick Fe islands on Cu(001). Two particles of the sample were prepared to have opposite magnetization by selective switching of one particle in an external field (a). After applying the stray field of a ferromagnetic STM tip to the left island, its magnetization has reversed (b).
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