High pressure study on a giant magnetoelectric effect hexaferrite via neutron techniques

Multiferroics have attracted tremendous research interests because of their potential in constructing next-generation multifunctional devices. Y-type hexaferrite Ba₂Mg₂Fe₁₂O₂₂ has promising magnetoelectric (ME) properties as a multiferroics which is sensitive to small magnetic field. When doped with Sr, the material keeps its sensitivity to field while the ME coefficients are greatly enhanced with Sr level increasing. Our previous work has reported new records of ME coefficients in single phase materials shown on Ba₂Mg₂Fe₁₂O₂₂ with Sr doping that changes its ground state spin cone symmetry. Temperature dependent neutron diffraction investigation shows pinning effect emerging at heavy Sr doped sample that also change to be an alternating longitudinal conical ground state. Applying hydrostatic pressure has different effects on these simultaneously occurred phenomena, indicating their relatively independent mechanisms. With recent progress of diamond anvil cell (DAC) at the HB-3A beamline, we are able to identify interesting pressure effect picture up 7.3 Gpa on the system magnetic states.