Spin-Flop Transition in Co2B2O5 Pyroborate

Temperature- and Field-Induced Transformation of the Magnetic State in Co2.5Ge0.5BO5

“…Strong magnetic anisotropy is observed even in the paramagnetic phase (Figure ). We performed the analysis of the magnetic susceptibility using an approach, which was earlier applied to other Co-containing borates: Co 3 BO 5 , Co 5/3 Nb 1/3 BO 4 , and Co 2 B 2 O 5 . The magnetic susceptibilities along the three directions as well as an average susceptibility obey the modified Curie–Weiss law in the T range 150–300 K where χ 0 is the temperature-independent term, C is the Curie–Weiss constant, and θ is the Curie–Weiss temperature.…”

“…Cobalt pyroborate Co 2 B 2 O 5 is a striking example where the long-range magnetic order is set through the nonmagnetic intermediate group BO 3 . This material can be obtained from the ludwigite by replacing the trivalent cobalt ion with boron and is antiferromagnet with the Neel temperature T N = 45 K. 48 Such isovalent substitution leads to a change in the structural type without changing the concentration of di-and trivalent cations per formula unit, i.e., keeping the ratio q = Me 2+ /(Me, B) 3+ equal to 1. This important parameter is responsible for the system's ability to form cationic charge-selected planes.…”

“…We performed the analysis of the magnetic susceptibility using an approach, which was earlier applied to other Co-containing borates: Co 3 BO 5 , 20 Co 5/3 Nb 1/3 BO 4 , 47 and Co 2 B 2 O 5 . 48 The magnetic susceptibilities along the three directions as well as an average susceptibility where χ 0 is the temperature-independent term, C is the Curie− Weiss constant, and θ is the Curie−Weiss temperature. The fit parameters are listed in Table 3.…”