The superexchange interactions and magnetic ordering in low-dimentional ludwigite Ni 5 GeB 2 O 10

Magnetic structure of Cu2MnBO5 ludwigite: thermodynamic, magnetic properties and neutron diffraction study

“…One can observe an anomalous behavior with a temperature peak at T c =88.1 K. The lattice specific heat was determined using linear combinations of the Debye-Einstein functions with the characteristic temperatures found to be T D = 331 K and T E = 780 K. It can be seen that the low temperature region isnot correctly interpolated. The same behavior was previously observed in another ludwigite crystal, Ni 5 GeB 2 O 10 [13]. Subtracting the lattice contribution to the specific heat from the experimental data, we found the excess specific heat and the phase transition entropy ∆S= 0.6 J/(mol*K).…”

“…Although the compound under study is dielectric, at temperatures close to zero, the specific heat decreases in accordance with the linear law, which were observed for all investigated ludwigites [13,22].…”

“…Such a separation of the magnetic system in two subsystems oriented nonparallel is apparently characteristic of all ludwigites; however, up to now the magnetic structure have been only studied for Fe 3 [4,13], which also evidence the occurrence of magnetization in two directions.…”

Ludwigites: From natural mineral to modern solid solutions

“…The field dependence of the magnetization has a “plateau” or “jumps” when the field is along the b axis. Similar behavior has been observed in some cobalt ludwigites: Co 5 TiBO 5 , CoMgGaBO 5 , the authors has attributed this behavior to the spin‐glass magnetic order, but Co 5 Sn(BO 5 ) 2 , in which such hysteresis loops behavior is observed, enters the magnetically ordered state at 82 K. In the case of nickel‐germanium ludwigite, such behavior is observed in a field in the only one direction, and possibly due to the partial reorientation of the sublattices .…”

Crystal Growth, Magnetic Properties and Analysis of Possible Magnetic Ordering of Ni5Sn(BO5)2 with Ludwigite Structure

“…The ludwigites Ni 5 Ge(BO 5 ) 2 , Ni 5 Zr(BO 5 ) 2 , and Ni 5 Ti(BO 5 ) 2 have a disordered distribution of nonmagnetic ions, with smaller (for Ge) or larger (for Ti and Zr) radii than the Sn ion. An interesting question is how the ordered distribution of Sn influences the magnetic properties of Ni 5 Sn(BO 5 ) 2 , and whether the unusual properties of Ni 5 Ge(BO 5 ) 2 arise . In a previous study, we reported the very interesting magnetic properties of Ni 5 Ge(BO 5 ) 2 .…”