Mag-O-Mat tutorial -> Setting Magnetization States Manually

Mag-O-Mat allows you to modify the magnetization states and the magnetic-anisotropic properties of selected areas of a component. It offers several ways (called modes) for specifying (editing) the properties of a component. Here, we will use the normal-array component of our first design group to illustrate the manual mode for specifying magnetization states.

In Mag-O-Mat select Group of different types of components in the Group box (the Component box should show Normal array component). Display this group alone in Magsimus by making the selection [1] Group of different types of components from the On display list.  In Mag-O-Mat select the Manual option in the Mode frame to initiate the manual setting of properties. If necessary click the toggle button above the map area (labeled Click to Zoom or Click to edit) once until it reads Click to Zoom (the annotation to the left should then read M Editing).  Not having the toggle button in this state, will cause mouse actions to zoom in the map box (see the section Zooming actions below).

Make sure that Magnetic state is selected in Characteristic box under the Material properties tab area to the right of the map box (a close-up is shown in Fig. 6). This will allow you to be able to make changes to the magnetization state of the sample. The second choice in this box (Anisotropy) allows you to define anisotropic properties for the sample -- this is discussed in the next topic following this one. The magnetization vectors of the cells are represented by the arrows in the map. The colors of the arrows depend on the value of the (normalized) vector component (MU, MV or MW) which is specified in Code value drop-down list, and which are mapped by the graded color strip next to the Code value box. The colors of the color strip (also called  a color wheel) can be modified using the Color wheel editor  ( Fig. 7) which is displayed by clicking the Edit color wheel button.

Fig. 6. Up-close view of Mag-O-Mat's Material properties tab with magnetic-state inputs displayed.

Fig. 7. Dialog boxes for editing Mag-O-Mat's color wheel. In the Color wheel editor (a) the vertical color strip below Sample wheel shows the current state of the color wheel as a blending of the colors displayed in the Color grade frame. Making a selection in this frame and clicking the Edit color button, displays the standard Windows™ Color dialog box (b) which can be used to alter the color of the selected part of the color wheel.

You will now manually select (using mouse actions) an area of the map where the magnetization state would be changed. Use the mouse to "sweep out" the rectangular region shown in Fig. 8a as follows: Click and hold down the left mouse button on a corner cell in the map; without releasing the mouse button drag the mouse until the displayed rectangular "rubber band" encompasses some cells as shown in the figure, and then release the mouse. The cell outlines of the traced out region will now be drawn in green as in Fig. 8b. This indicates that their magnetization vectors are ready to be changed. The input area below the Characteristic box is now enabled. Make the following entries in this area: In the Theta frame, Mean = 90, Dev = 0  and in the Phi frame, Mean = 45, Dev = 10. These entries represent the mean values and deviations of the polar angular coordinates of the magnetization vectors in the specified map region. Theta denotes the polar angle measured from W-axis and of the component (refer to the section Navigating components below) while Phi denotes the azimuthal angle measured from the U-axis. The angular orientations are assigned randomly about the mean values to extents limited by the given angular deviations. Click the Accept button to apply these entries to the map, which should now look like Fig. 8c, reflecting the newly-specified magnetization state.

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Fig. 8.  Figures for manual-mode setting of magnetization properties discussed in the text

Next, sweep out a new map region similar to that shown in Fig. 9a. Make the entries Mean = 45, Dev = 0, in the Theta frame and Mean = -135, Dev. = 0, in the Phi frame and click the Accept button. The map box should now look like Fig. 9b. The magnetization in the above two regions are colored differently due to their different U-components. The ways you change these colors are by editing the color wheel (Fig. 7) or by making a different selection in the Code value box (try some of these out to see their effects). Click the Transfer button above the map box to apply the defined Magnetization state to Magsimus. Your Magsimus System-view box should now look like Fig. 9c.

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Fig. 9.  Figures for manual-mode setting of magnetization properties discussed in the text

It should be noted that even though the magnetization vectors in the Magsimus (or any other MagOasis application software) session are color coded (as determined by the appropriate settings of available display-attribute flags), these need not necessary match the colors used for the magnetization vectors in Mag-O-Mat. For the colors to match, you need to explicitly specify them as such.

Zooming actions

You can zoom in and out of various regions of the map in order to view them closely and possibly facilitate the accurate changing of their magnetic state or anisotropy properties. This is especially useful for resolving the details of different parts of very dense maps that are produced by components with very large cell grids. Let us illustrate how to zoom into a region of the map. In Mag-O-Mat click the toggle button above the map area (currently labeled Click to Zoom); the annotation to the left should now read Zooming (and the toggle button will read Click to edit).   Sweep out the intended zoom region shown in Fig. 10a by holding down and dragging the left-mouse mouse as described previously.  Release the mouse. The defined zoom region is now displayed to fill up the map window (Fig. 10b).   Any number of subsequent zooms can be carried out. Double-click the mouse anywhere inside the map box to revert back to the un-zoomed state (do it).

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Fig. 10. Figures illustrating zooming actions discussed in the text.

Note that you can resume changing the media properties after zooming into a map, by clicking the toggle button (its label will change to Click to Zoom) and proceeding as before.

Navigating components

In addition to being able to zoom into different areas of a map, Mag-O-Mat provides other means to flexibly “move through” a component using the controls under the Array layout tab to the right of the map box. These controls are shown up close  in Fig. 11.

Fig. 11. Up-close view of Array layout tab.

MagOasis software associates each design component with a local (UVW) Cartesian coordinate system. The Map axes box presents a schematic of the coordinate axes of the map relative to its current map view. In the lesson so far you have had the map box display a U – V projection of the sample.  You can change this projection by making the appropriate selection (U – V, U – W or V - W) in the Map plane frame.

The component can be considered a stack of parallel layers (or slices) in the direction of the normal to the projection plane. You display a layer by entering its position in the input box (1) or by moving the slider (2) as needed. Thus, access to different regions of a three-dimensional array object is achieved by appropriate choices of array planes and their positions. Clicking the Center array button selects the mid array-plane position and displays it in the map box. It is instructive to try out some of these controls at this time, to familiarize yourself with how they work.

Round up

The manual modifications of magnetic states discussed here captures the essence of the general steps for specifying and applying media properties using Mag-O-Mat: First, you define the properties locally in the Mag-O-Mat map box using any of the available map-region selection modes. You then transfer the new properties  to the component in the external application session, by pressing the Transfer button. In the next topic you will learn how to manually define new media anisotropy characteristics. In subsequent topics you will learn how to define new characteristics using standard built-in shapes and external masks.