A magnetic cell core includes at least one stressor structure proximate to a magnetic region (e.g., a free region or a fixed region). The magnetic region may be formed of a magnetic material exhibiting magnetostriction. During switching, the stressor structure may be subjected to a programming current passing through the magnetic cell core. In response to the current, the stressor structure may alter in size. Due to the size change, the stressor structure may exert a stress upon the magnetic region and, thereby, alter its magnetic anisotropy. In some embodiments, the MA strength of the magnetic region may be lowered during switching so that a lower programming current may be used to switch the magnetic orientation of the free region. In some embodiments, multiple stressor structures may be include in the magnetic cell core. Methods of fabrication and operation and related device structures and systems are also disclosed.