The first polarised neutron reflectivity from a magnetic sample has been measured using the polarisation system of our time-of-flight reflectometer PLATYPUS.
The sample under test was a thin film (~750 Å) of Nickel on a silicon substrate, magnetised with a 1T electromagnet (Bruker) at the sample stage.
The neutrons are polarised using a (m=4) Fe/Si supermirror which reflects the unwanted spin direction and transmits the desired spin. After reflection from the sample the neutron spins are analysed with a similar supermirror before detection.
Further control of the neutron spin is made possible by two radio frequency spin flipper coils. All the gaps between each of the optical elements are equipped with a magnetic guide field to maintain the neutron spin direction.
The figure shows the first data recorded with both polarisation and analysis of the neutron spin in comparison with an unpolarised neutron beam. This first commissioning phase of the polarisation system confirmed the expected operation of all polarisation components.
Published: 21/10/2009