Piezomagnetism
The Piezomagnetism multiphysics node () passes the appropriate magnetization contribution from the Piezomagnetic Material node in the Solid Mechanics interface (where it is defined together with the magnetoelastic properties of the material) to the Ampère’s Law, Piezomagnetic node in the Magnetic Fields interface. It also passes the mechanics stress contribution due to the applied magnetic field back to the Piezomagnetic Material node.
Instead of Magnetic Fields interface, you can also use Rotating Machinery, Magnetic interface.
Settings
The Label is the multiphysics coupling feature name. The default Label (for the first multiphysics coupling feature in the model) is Piezomagnetism 1.
The Name is used primarily as a scope prefix for variables defined by the coupling node. Refer to such variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different coupling nodes or physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.
The default Name (for the first multiphysics coupling feature in the model) is pzm1.
Coupled Interfaces
This section defines the physics involved in the Piezomagnetism multiphysics coupling. The Solid mechanics and Magnetic fields lists include all applicable physics interfaces.
The default values depend on how the Piezomagnetism node is created.
•
If it is added from the Physics ribbon (Windows users), Physics contextual toolbar (macOS and Linux users), or context menu (all users), then the first physics interface of each type in the component is selected as the default.
•
If it is added automatically when The Piezomagnetism Interface is selected in the Model Wizard or Add Physics window, then the participating Solid Mechanics and Magnetic Fields interfaces are selected.
You can also select None from either list to uncouple the Piezomagnetism node from a physics interface. If the physics interface is removed from the Model Builder, for example Solid Mechanics is deleted, then the list defaults to None as there is nothing to couple to.
If a physics interface is deleted and then added to the model again, then in order to reestablish the coupling, you need to choose the physics interface again from the lists. This is applicable to all multiphysics coupling nodes that would normally default to the once present interface. See Multiphysics Modeling Workflow in the COMSOL Multiphysics Reference Manual.
Domain Selection
The domain selection includes by default all applicable domains. Such domains represent an intersection of the applicable domains under the corresponding Magnetic Fields and Solid Mechanics interfaces selected in the coupling feature.
In Magnetic Fields interface, the following domain feature is applicable:
•
Ampère’s Law, Piezomagnetic
In Solid Mechanics interface, the following domain feature is applicable:
•
Piezomagnetic Material.
For nonsolid magnetic domains, remove them from the Solid Mechanics interface selection but keep them selected in the Magnetic Fields interface selection.
Coupling Type
From the list, choose one of these coupling types:
•
 Fully coupled (the default) to include both the direct and inverse piezomagnetic effects.
•
 Joule effect, also known as direct piezomagnetic effect, to include only the deformation of the material caused by its magnetization in response to the applied magnetic field.
 Villari effect, also known as inverse piezomagnetic effect, to include only the change in the material magnetization as a result of applied mechanical stress or strain.