Year: 2026
Type: preprint
Abstract: Spin-driven multiferroics owe their electric polarization to lattice distortions that follow the magnetic order, yet in incommensurate magnets symmetry normally forbids such a distortion at the fundamental magnetic wavevector, and the distortions themselves are rarely observed. Here we use half-polarized neutron scattering to show that the Y-type hexaferrite Ba$_{0.4}$Sr$_{1.6}$Mg$_2$Fe$_{12}$O$_{22}$ hosts, in its saturated high-field state, a magnetic modulation and a longitudinal lattice modulation at one and the same wavevector, locked in phase. The signature is a large nuclear-magnetic interference asymmetry, $r$ ~ 0.8, of the same sign at the two conjugate satellites and persisting to 275 K. The zone contrast and the field dependence of the satellite indicate an internal, field-induced longitudinal distortion. The modulated state coexists with the transverse-conical magnetoelectric phase and outlives it, revealing a fundamental-wavevector spin-lattice coupling in a magnetic field regime previously regarded as a simple ferrimagnet.
Source: arXiv (Cornell University)
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Awards: G1324702760, Scattering studies of emergent phenomena at extreme conditions of magnetic field and temperature., Wide-angle neutron polarisation analysis to study energy and quantum materials, G4152820556, G7101456536, Accessing high pressure and low temperature states of exotic magnetism, G966035586
OpenAlex ID: W7221748567