In situ magnetometry with polarized neutrons on thin magnetic films

We shall discuss perspectives opened up by using polarized neutron reflecto metry as an in situ technique to measure the magnetization of ultrathin fil ms not covered by a protective layer. In order to demonstrate the advantage of this method, Fe(110) films of a thickness of up to 20 Angstrom were pre pared on V(110) single crystals. In neutron measurements the absolute value of the magnetization of the films was determined precisely by a simple opt ical model, by fitting the spin-up and spin-down reflectivities separately. Additionally the measurements were compared with data obtained from magnet o-optical Kerr magnetometry. Both techniques show that the magnetizations o f the films are considerably reduced. [S0163-1829(99)12033-2].