A method of manufacturing a magnetic core includes providing a substrate with magnetically permeable material that has a first region and a second region near the first region, providing support to maintain a juxtaposition between the first region and the second region, forming a slit through the magnetically permeable material between the first region and the second region, introducing a binding agent into the slit and removing the support; wherein the binding agent maintains the juxtaposition between the first region and the second region after the support is removed.