Magnetic phase diagram and first-principles study of Pb 3 TeCo 3 v 2 O 14

Abstract

An antiferromagnetic ordering in Pb3TeCo3V2O14 takes place through formation of a short-range correlation regime with T* ∼ 10.5 K and the succession of a second-order phase transition at TN1 = 8.9 K and a first-order phase transition at TN2 = 6.3 K. An external magnetic field rapidly destroys magnetic structure at T < TN2 and influences the magnetic order at TN2 < T < TN1, resulting in a complex magnetic phase diagram of Pb3TeCo3V2O14 as derived from magnetization and specific heat measurements. The first-principles calculations indicate that, in variance with a layered crystal structure, the magnetic subsystem of Pb3TeCo3V2O14 is quasi-one-dimensional and highly unusual, consisting of weakly coupled triangular tubes. © 2014 American Physical Society.