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

Abstract

Abstract-We report on the thermodynamic, magnetic properties and the magnetic structure of ludwigite-type Cu 2 MnBO 5 . The specific heat, the low-field magnetization and the paramagnetic susceptibility were studied on a single crystal and combined with powder neutron diffraction data. The temperature dependence of the specific heat and the neutron diffraction pattern reveal a single magnetic phase transition at T=92 K, which corresponds to the magnetic ordering into a ferromagnetic phase. The cation distribution and the values and directions of magnetic moments of ions in different crystallographic sites are established. The magnetic moments of Cu 2+ and Mn 3+ ions occupying different magnetic sites in the ferrimagnetic phase are pairwise antiparallel and their directions do not coincide with the directions of the principal crystallographic axes.The small value of the magnetic moment of copper ions occupying site 2a is indicative of partial disordering of the magnetic moments on this site. The magnetization measurements show a strong temperature hysteresis of magnetization, which evidences for field-dependent transitions below the phase transition temperature.

Crystal formation of Cu-Mn-containing oxides and oxyborates in bismuth-boron fluxes diluted by MoO3 and Na2CO3

“…The synthesis of the oxyborates with warwickite and ludwigite structures is the problem of high complexity. In these structures, there is a simultaneous presence of the metal cations with valence states (2+ and 3+) or (2+ and 4+) and they demonstrate high sensibility of the physical properties to small changes of composition [15][16][17][18][19]. In oxyborates Mn 2+ 1-x Cu x Mn 3+ BO 4 and Mn 2+ 2-x Cu x Mn 3+ BO 5 with warwickite and ludwigite structures, respectively, the manganese cations are in different valence states.…”

“…2-x Cu x Mn 3+ BO 5 and Mn 2+ 1-x Cu x Mn 3+ BO 4 oxyborates The study of crystallization presented in this work focuses on the investigation of the mechanisms and the intermediate chemical bonds in the fluxes (1) aimed to synthesize the Mn 2+ 2-x Cu x Mn 3+ BO 5 and Mn 2+ 1-x Cu x Mn 3+ BO 4 oxyborates with ludwigite and warwickite structures respectively. These compound contain the manganese in different valence states and have quasi-low-dimensional structures formed by ribbons, zig-zag walls and three-leg ladders [16][17][18][19][20]. The unit cells of these compounds are characterized by high Z (Z=4 for both structures) and by several nonequivalent positions of heterovalent magnetic cations (4for ludwigite structure and 2for warwickite structure).…”

“…The unit cells of these compounds are characterized by high Z (Z=4 for both structures) and by several nonequivalent positions of heterovalent magnetic cations (4for ludwigite structure and 2for warwickite structure). These structural features are of great influence to electrical and magnetic properties of ludwigites and warwickites [16][17][18][19][20].…”

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

“…These geometrical features of the structure are expected to lead to frustrations. The noncollinear ordering in Fe 3 BO 5 and Cu 2 MnBO 5 appears due to the frustration of the exchange interactions between subsystems. In the case of Ni 5 Sn(BO 5 ) 2 , one of the subsystems contains nonmagnetic ions of Sn.…”

Structure and Properties of the Non‐Centrosymmetric Manganese(II) Borate Mn5(BO3)3OH

“…Transition metal (TM) ludwigites (TM1 3-x TM2 x O 2 BO 3 ) exhibiting phenomena like the magnetization pole reversal in Mn 3-x Ni x O 2 BO 3 and the spin-glass magnetic ordering in Co 3-x Mn x O 2 BO 3 , were subjects of intense scrutiny. [25][26][27][28][29] As high pressure/high temperature approaches proved to be a great gain in the exploration of new crystalline materials, [30] we were motivated to further investigate and extend this field.…”