Arrangement for producing a constant magnetic field

An arrangement for generating a constant magnetic supporting field for a magnetic cylindrical domain store, comprising a magnetic matrix of at least two magnetic plates having soft magnetic properties arranged plane-parallel to each other and separated by an interval gap, and two bar-shaped permanent magnets located within said interval gap between said plates and arranged concurrently and substantially apart, said permanent magnets having their longitudinal middle axes parallel to each other and magnetized perpendicularly thereto, at least one of said permanent magnets rotatable about its longitudinal axis, a store carrier for holding said domain store in said supporting field, and a U-shaped carrier comprising a means for mounting and aligning said soft magnetic plates and having magnetically non-conducting properties of only low thermal expansion, wherein each of said bar-shaped permanent magnets is rotatably mounted between the legs of said U-shaped carrier.