Structural and magnetic properties of the oxyborateCo5Ti(O2BO3)2

Abstract

We present an extensive study of the oxyborate material Co 5 Ti͑O 2 BO 3 ͒ 2 using x-ray, magnetic, and thermodynamic measurements. This material belongs to a family of oxyborates known as ludwigites which presents low-dimensional subunits in the form of three leg ladders in its structure. Differently from previously investigated ludwigites the present material does not show long-range magnetic order although it goes into a spin-glass state at low temperatures. The different techniques employed in this paper allow for a characterization of the structure, the nature of the low-energy excitations and the magnetic anisotropy of this system. Its unique magnetic behavior is discussed and compared with those of other magnetic ludwigites.

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

“…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.…”

“…The magnetic phase transition entropy obtained using formula (1) exceeds by far the experimental value. This difference is indicative of the absence of complete ordering of the magnetic moments at this magnetic phase transition, which agrees with the resultsfrom the neutron magnetic scattering data.The partial ordering of the magnetic moments is characteristic of heterometallic ludwigites, which contain two or more magnetic ions [2,3]. The homometallic ludwigites Fe 3 BO 5 [10,11,21] and Co 3 BO 5 [12,21] are characterized, on the contrary, by the long-range magnetic order.…”

“…An important feature of the Co 3 BO 5 and Fe 3 BO 5 ludwigites is the division of the magnetic structure into two subsystems. In Fe 3 BO 5 , which sees a charge ordering transition just below room temperature, the magnetic subsystems order at different temperatures with mutually orthogonal magnetic moments [11]. The Co 3 BO 5 ludwigite displays a single magnetic transition with the presence of an ordered arrangement of low spin and high spin states of the Co 3+ ions (S Co3+ =0) [12].…”

Structure and magnetism of copper-substituted cobalt ludwigite Co3O2BO3

“…These oxyborates may crystallize into a large variety of crystallographic structures named after the natural minerals: calcite, hantite, pyroborate, cotoite, warwickite and ludwigite [1][2][3][4][5]. The latter compounds known as ludwigites at last few years forced the high wave of interest due to their extremely unusual magnetic properties [6][7][8][9][10]. For example, one from two known homometallic ludwigites Fe 3 O 2 BO 3 seems to possess at least two magnetic sublattices, which order orthogonally at temperatures 110 and 70 K [7,9].…”

Frequency-temperature dependent dynamics of dielectrics in ferric oxoborate Fe3BO6 of cocktail structure of nanorods

“…The compound Fe 3 BO 6 belongs to an important family of iron oxoborates Fe 2þ Fe 3þ OBO 3 , Fe 2þ 2 Fe 3þ O 2 BO 3 , or Fe 3þ 2 Fe 3þ O 3 BO 3 and displays highly tailored electronic properties depending on iron valence Fe 2þ , Fe 3þ , and relative O 2À number density in a space lattice [1][2][3][4][5][6][7][8]. A canted antiferromagnet of 3d 5 (Fe 3þ ) spins on an infinitely large space lattice Fe 3 BO 6 displays a magnetic orientational phase transition from one weak ferromagnet state À 2 to another À 4 [3,9].…”