Applications of remanent supermirror polarizers

Recent developments in sputtering techniques allow the fabrication of multi layers with a high degree of perfection over large areas. We show, that usi ng reactive sputtering, it is possible to adjust the index of refraction fo r neutrons, n(i) of the individual layers. This property is particularly im portant for polarizing mirrors, where n(nm) for the non-magnetic layers can be matched to n(m) of the magnetic layers such that neutrons for one spin- eigenstate are not reflected by the coating, whereas the reflectivity is hi gh for the other spin-eigenstate. In addition, by using anisotropic sputter ing conditions it is possible to orient the easy axis of magnetization with in the plane of the mirrors in any particular direction resulting in a simu ltaneous appearance of a pronounced remanence and coercivity. Remanent pola rizers can be used as broad band spin selectors at continuous and in partic ular at pulsed neutron sources thus eliminating the need of spin flippers, whose performance depends on the wavelength of the neutrons and is often st rongly influenced by stray magnetic fields from the sample environment. The possibility to operate remanent supermirrors in arbitrary small fields lea ds to attractive applications of polarizing devices in low held environment s such as they occur in neutron-spin-echo or in spin selective neutron guid es. We present applications, where several tasks like polarizing, focusing and spin selection are performed in one single device thus reducing the pro blem of phase space matching between different neutron optical components. (C) 1999 Elsevier Science B.V. All rights reserved.