Magnetic properties and magnetic structure of the Ba_(2)Mn(PO_(4))_(2) antiferromagnet featuring frustrated zigzag chains of S?52 Mn^(2+)ions are reported based on neutron diffraction,density-functional bandstructure ...Magnetic properties and magnetic structure of the Ba_(2)Mn(PO_(4))_(2) antiferromagnet featuring frustrated zigzag chains of S?52 Mn^(2+)ions are reported based on neutron diffraction,density-functional bandstructure calculations,as well as temperature-and field-dependent measurements of magnetization and specific heat.A magnetic transition at TN■5 K marks the onset of the antiferromagnetic order with the propagation vector k=(1/2 0 1/2)and the ordered moment of 4.33±0.08μB/Mn^(2+)at 1.5 K,pointing along the c direction.The direction of the magnetic moment is chosen by single-ion anisotropy,which is relatively weak compared to the isostructural Ni^(2+)compound.Geometrical frustration has a strong impact on the thermodynamic properties of Ba_(2)Mn(PO_(4))_(2),but manifestations of the frustration are different from those in Ba_(2)Ni(PO_(4))_(2),where frustration by isotropic exchange couplings is minor,yet strong and competing single-ion anisotropies are present.A spin-flop transition is observed around 2.5 T.The evaluation of the magnetic structure from the ground state via the spin-flop state to the field-polarized ferromagnetic state has been revealed by a comprehensive neutron diffraction study as a function of magnetic field below TN.Finally,a magnetic phase diagram in the H-T plane is obtained.展开更多
文摘Magnetic properties and magnetic structure of the Ba_(2)Mn(PO_(4))_(2) antiferromagnet featuring frustrated zigzag chains of S?52 Mn^(2+)ions are reported based on neutron diffraction,density-functional bandstructure calculations,as well as temperature-and field-dependent measurements of magnetization and specific heat.A magnetic transition at TN■5 K marks the onset of the antiferromagnetic order with the propagation vector k=(1/2 0 1/2)and the ordered moment of 4.33±0.08μB/Mn^(2+)at 1.5 K,pointing along the c direction.The direction of the magnetic moment is chosen by single-ion anisotropy,which is relatively weak compared to the isostructural Ni^(2+)compound.Geometrical frustration has a strong impact on the thermodynamic properties of Ba_(2)Mn(PO_(4))_(2),but manifestations of the frustration are different from those in Ba_(2)Ni(PO_(4))_(2),where frustration by isotropic exchange couplings is minor,yet strong and competing single-ion anisotropies are present.A spin-flop transition is observed around 2.5 T.The evaluation of the magnetic structure from the ground state via the spin-flop state to the field-polarized ferromagnetic state has been revealed by a comprehensive neutron diffraction study as a function of magnetic field below TN.Finally,a magnetic phase diagram in the H-T plane is obtained.
