Antiferromagnetism of the cation-ordered warwickite system Mn2-Mg BO4 (x = 0.5, 0.6 and 0.7)

Abstract

Single crystals of Mn2-xMgxBO4 (x=0.55, 0.63, and 0.67) solid solutions were obtained using flux synthesis. A monoclinic P121/n1 symmetry similar to the end member Mn2BO4 is found for all samples. Regular cation and charge distributions over two non-equivalent metal sites are observed. DC magnetization and heat capacity measurements reveal an AFM ordering at TN= 16, 14 and 13 K for x=0.55, 0.63, and 0.67, respectively. The prerequisites for the occurrence of cation and magnetic orderings in heterometallic warwickites are discussed.

Near ultraviolet light excitable highly efficient blue-green multicolour warwickite phosphor, ScCaO(BO3):Ce3+, Tb3+

“…[29][30][31][32] We focused on ScCaO(BO 3 ) (SCBO) crystal structure that was first reported by Ma et al from the single crystal X-ray diffraction, which is in agreement with warwickite such as MgScO(BO 3 ), YCaO(BO 3 ), and Mg 0.76 Mn 1.24 O(BO 3 ), respectively. [33][34][35][36] The warwickite structure is composed of two disordered octahedral sites containing divalent (M 2+ ) and trivalent (M 3+ ) metal ions. The SCBO crystal structure contains CaO 6 and ScO 6 octahedra that are present, whereas, the other warwickite structures contain two disordered octahedra, (M 3+ /M 2+ )O 6 .…”