Mag-O-Mat tutorial -> Setting Properties using Shape Mode

In the current topic you will learn how to specify media properties in shape mode. For this lesson only the magnetic state of the sample will be modified, however, all that will be discussed will apply equally well when specifying anisotropy, with the only difference being the input characteristics you enter.

In the shape mode you create new media properties by selecting one of Mag-O-Mat’s built-in shapes. Unlike the manual method which acts only on the active layer (displayed in the map window), the properties specified in the shape mode apply to the sample as a whole.

Begin by selecting the Shape option in the Mode frame of Mag-O-Mat.  You will work with a different component from the one we used in the previous section. In the Group box select Group of one normal material array. This group contains the array component Pseudo-soft array which is listed in the Components box. The map box currently contains a U-V projection of the sample. Change this by selecting U-W in the Map plane frame (the map is re-drawn accordingly) of the Array layout tab. Specify a different color coding for the magnetization vectors in the map box by selecting MW in the Code value box of the Materials properties tab. Display the group alone in the Magsimus session by selecting [2] Group of one normal material array in the On display list. Your Mag-O-Mat map box and Magsimus System-View window should now look like Fig. 16a and Fig. 16b.

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Fig. 16.  Figures for shape-mode setting of magnetization states discussed in the text.

You will change the magnetic state within an ellipsoidal region of the sample. But first, you will carry out a few needed actions to prepare for this. As usual make sure that the toggle button above the map area of Mag-O-Mat reads Click to Zoom (you may need to click the toggle button once to achieve this). This ensures that we will be creating properties and not performing zoom actions in the map box. Select Magnetic state in the Characteristic box of the Material properties tab.

Next, you will select the shape for the region in which the new properties will take effect and apply it to the map box. Back in the Mode frame select the Ellipsoid from the drop-down list box to the right of the Shape option. A pictorial representation of the shape selection you make in this box is displayed in the Shape inputs frame next to it (click here to learn more about built-in shape properties). Make sure that Grid inputs is selected from the Shape input type drop-down list. This means that input parameters (for example the a-input of the cone in the Shape inputs box) are expressed in terms of number of cells. The other selection Length inputs will result in inputs being interpreted as normal length inputs.

By default, the shape we selected will span the whole map region. You will now define a smaller map region instead.  Using standard mouse actions sweep out new extents for the shape as shown in Fig. 17a (the rectangle will remain in place after releasing the mouse). Enter the following values in the Shape inputs frame: u-Diam, a = 10 and w-Diam, c = 10. These inputs will ensure that the ellipsoid will be completely contained within the region we traced out in the map box. Click the Apply shape button. The ellipsoidal shape is transferred to the map box, and the color of the cell outlines within the region defined by this shape will change to green (Fig. 17b). In the Magnetic state frame of the Materials properties tab, make the following entries: Set Mean = 90 and Dev. = 0 in the Theta frame and in the Phi frame enter Mean = 0 and Dev. = 15. Click the Accept button to apply the new magnetic state to the ellipsoidal region of the map (Fig. 17c). Click Transfer button above the map window to transfer the new state to Magsimus. The display of the component in Magsimus should now look like Fig. 17d.

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Fig. 17.  Figures for shape-mode setting of magnetization states discussed in the text.

Round up

In this section you learned how to easily create new media characteristics in Mag-O-Mat using built-in shapes. The example illustrated the use of this technique to change the magnetic state of a sample. The exact same procedure is applicable when creating new anisotropy properties, with the exception that you make the selection Anisotropy from the Characteristic list box and specify the associated anisotropy inputs.

The full extent of the map window is selected as the region for applying a shape to the map box (by clicking the Apply shape). As was demonstrated in this lesson you can specify a smaller region using the mouse.  The extents of the active region are reverted back to the default whenever you change the map plane. You can carry out the usual map zoom actions after clicking the toggle button above the map window so that it reads Click to edit.