We have succeeded in precisely measuring spin-precession angles of tunnelin
g and nontunneling neutrons through double-rectangular, triple-rectangular,
and multirectangular potential barriers represented by a [Permalloy45(PA)-
germanium(Ge)](n)-PA Fabry-Perot magnetic thin-him resonator for n =1, 2, a
nd 10, respectively. The spin-precession angle due to the Fabry-Perot reson
ator shows the oscillation curve as a function of the incident angles, and
the curve is well reproduced by the theoretical phase difference of up arro
w and down arrow spin neutron wave functions based on the one-dimensional S
chrodinger equation. We demonstrate that the amplitude of the curve is prop
ortional to the number of germanium layers (wells) although the transmissio
n probability remains constant.