Evolution of the 2D antiferromagnetism with temperature and magnetic field in multiferroic Ba${}_2$CoGe${}_2$O${}_7$

Abstract

We report on spherical neutron polarimetry and unpolarized neutron diffraction in zero magnetic field as well as flipping ratio and static magnetization measurements in high magnetic fields on the multiferroic square lattice antiferromagnet Ba${}_2$CoGe${}_2$O${}_7$. We found that in zero magnetic field the magnetic space group is $C{m}^{\prime }m{2}^{\prime }$ with sublattice magnetization parallel to the [100] axis of this orthorhombic setting. The spin canting has been found to be smaller than $0.2^{\circ }$ in the ground state. This assignment is in agreement with the field-induced changes of the magnetic domain structure below 40 mT as resolved by spherical neutron polarimetry. The magnitude of the ordered moment has been precisely determined. Above the magnetic ordering temperature short-range magnetic fluctuations are observed. Based on the high-field magnetization data, we refined the parameters of the recently proposed microscopic spin model describing the multiferroic phase of Ba${}_2$CoGe${}_2$O${}_7$.

References in corpus (5)

• Non-collinear spin-density wave antiferromagnetism in FeAs
• Spin-stretching modes in anisotropic magnets: spin-wave excitations in the multiferroic Ba2CoGe2O7
• Multiboson spin-wave theory for Ba2CoGe2O7, a spin-3/2 easy-plane Neel antiferromagnet with strong single-ion anisotropy
• Multiferroic properties of an åkermanite Sr${}_2$CoSi${}_2$O${}_7$ single crystal in high magnetic fields
• Magnetic structure of RuSr${}_2$GdCu${}_2$O${}_8$ determined by resonant x-ray diffraction

Cited by in corpus (5)

• Direct observation of spin-quadrupolar excitations in Sr${}_2$CoGe${}_2$O${}_7$ by high field ESR
• Magnetization induced local electric dipoles and multiferroic properties of Ba2CoGe2O7
• Spin Hall magnetoresistance at the altermagnetic insulator/Pt interface
• Magnetic excitations in the noncentrosymmetric magnet Sr2MnSi2O7
• Dipolar-driven mean-field criticality in the ferrimagnet Eu${}_2$MnSi${}_2$O${}_7$