The use of diamond-shaped graphene nano-patches as novel non-volatile switching elements exhibiting transitions between high and low conductance states based on changes of magnetic ordering of these states. Non-magnetic reconstructed graphene nano-ribbons are used as non-invasive leads to implement the switching elements as carbon-nanoflake based memories and transistors. Switching of the elements may be implemented by electric-field-induced altering of the magnetic state. Graphene nano-patch shapes of certain geometries provide passive electric-field sources such as to establish initial bits of information saved in graphene-based memories.