Electron Holography, Aharonov-Bohm Effect and Flux Quantization

Electron holography was employed to experimentally confirm the Aharonov-Bohm effect. Phase difference was measured between two electron waves passing through two spaces inside and outside a tiny toroidal ferromagnet, which has a completed circuit of magnetic flux. These measurements agreed with theoretical values within 10%. The possibility of flux quantization in h/e or h/2e units was experimentally negated, giving a further definite evidence that the Aharonov-Bohm effect exists.