pH-controlled polymorphism in a layered dysprosium phosphonate and its impact on the magnetization relaxation

Abstract

Two polymorphic layered dysprosium phosphonates α-Dy(2-qpH)(SO₄)(H₂O)₂ (α-Dy) and β-Dy(2-qpH)(SO₄)(H₂O)₂ (β-Dy) (2-qpH₂ = 2-quinolinephosphonic acid) which crystallize in monoclinic P2₁/c and triclinic P space groups, respectively, are reported. Both exhibit field-induced slow relaxation of magnetization at low temperature. The energy barrier for β-Dy is nearly three times that for α-Dy, attributed to the structural differences in the two phases.