Magnetic excitations of uniaxial-strain detwinned FeSe

We propose to measure intrinsic magnetic excitations of FeSe detwinned by a newly-developed strain device based on differential thermal expansion of invar alloy and aluminium. Though magnetic excitations of twinned FeSe and low-energy (E<10meV) spin fluctuations have been measured with neutron scattering, much concerning the intrinsic magnetic excitations are still unknown and need to be explored in detwinned FeSe. With the new device with large amount (2 grams) of FeSe glued on aluminium sheets, we will measure the magnetic excitations at (1,0), (0,1) and (1,1) upto 60meV at various temperature across superconducting and structural transitions, from which the nematic spin correlations and the nature of the magnetic excitations at (1,1) will be determined.