A resonance spin flipping of polarised neutrons studied on magnetic cluster structures

Polarised neutron transmission T(±) studies are performed in applied external magnetic fields versus neutron wavelength on a Li‐Ti‐Zn ferrite system exhibiting a magnetocrystalline cluster structure. Distinct maxima for transmission T(‐), measured at negative polarisation P−, are observed and interpreted as due to the resonance spin flipping of neutrons. This resonance spin flipping is noticed for the first time on a dynamic magnetic cluster system in which the external magnetic field produces a rotating magnetic induction 〈B〉⊥, perpendicular to the constant guiding magnetic induction 〈B〉∥. Polarised neutrons passing through this system interact with a rotating magnetic induction 〈B〉(t) connected with the correlated interaction of cluster oscillators. Based on the observed resonance maxima of neutron transmission T(−), the perpendicular 〈B〉⊥ and parallel magnetic induction 〈B〉∥, as well as the length of the periodicity of the 〈B〉⊥ component “seen” by the neutrons are determined. The values of 〈B〉⊥ and 〈B〉∥ are in good agreement with those obtained previously by us in neutron depolarisation experiments. Moreover, magnetic “cluster waves”, induced by the external magnetic field are observed. It is found that the generated “cluster waves” in a coupled cluster system propagate with the velocity of vr ≈ 344 m/s. The mean gyromagnetic ratio γc of magnetic clusters is also determined as γc ≈ −2.18 × 105 rad/s mT or γc ≈ −3.47 × 104 Hz/mT.