The low-temperature thermodynamic properties and magnetic structure of the garnet oxide ${\mathrm{Mn}}_3{\mathrm{V}}_2{\mathrm{Ge}}_3{\mathrm{O}}_{12}$ (MVGO) have been investigated via magnetic susceptibility, specific heat, and neutron diffraction measurements. MVGO exhibits two successive magnetic transitions at $T_{\mathrm{N}1}=4\mathrm{K}$ and $T_{\mathrm{N}2}=2.6\mathrm{K}$, associated with the antiferromagnetic ordering of noncollinear ${\mathrm{Mn}}^{2+}$ and collinear ${\mathrm{V}}^{3+}$ sublattices, respectively. The Curie-Weiss analysis based on the susceptibility data and the magnetic entropy derived from the specific heat measurement confirmed the ground state $S=5/2$ for ${\mathrm{Mn}}^{2+}$ and $S=1$ for ${\mathrm{V}}^{3+}$. Density functional theory calculations reproduce the experimentally determined magnetic structures, yielding nearest-neighbor antiferromagnetic couplings $J_{\text{Mn-Mn}}$ and $J_{\text{V-V}}$ along with a ferromagnetic coupling $J_{\text{Mn-V}}$. By applying a magnetic field, we construct a temperature-field phase diagram for MVGO that encompasses multiple distinct phases. These results establish MVGO as a complex system among garnet-structure magnets.

Close

PrevNext

View figure in article

• Frustrated magnetism
• Magnetic order
• Manganites
• DFT+U
• Magnetization measurements
• Neutron scattering
• Specific heat measurements