Europium and manganese magnetic ordering in EuMn₂Ge₂

Abstract

The antiferromagnetic structures of both the manganese and europium sublattices in EuMn2Ge2 have been determined using thermal neutron diffraction. T(N)(Mn) = 714(5) K with the 3.35(5) μ(B) (at 285 K) Mn moments ordering according to the I4'/m'm'm space group. The Eu order is incommensurate with the 6.1(2) μ(B) (at 3.6 K) Eu moments oriented parallel to the c-axis with a propagation vector of k = [0.153(2) 0 0]. Both neutron diffraction and (151)Eu Mössbauer spectroscopy reveal evidence of magnetic short-range ordering of the Eu sublattice around and above T(N)(Eu) ∼ 10 K. The ordering temperature of the Eu sublattice is strongly affected by the sample's thermal history and rapid quenching from the melting point may lead to a complete suppression of that ordering.

Magnetic phase diagram of the solid solution LaMn2(Ge1-xSix)2 (0 ≤ x ≤ 1) unraveled by powder neutron diffraction

“…[14] The wide range of behavior exhibited by the REMn 2 X 2 materials is related to the rich diversity of collinear and non-collinear magnetic states that can be realized in this atomic arrangement. [15][16][17][18][19][20][21][22][23][24][25][26] Magnetic ordering temperatures between 300 K and 714 K have been observed for all compounds of this type, [1,27] and many of them undergo several magnetic transitions upon cooling before they reach their magnetic ground state. Previous studies on various solid solutions based on REMn 2 X 2 indicated that the Mn-Mn distances play a major role in the formation of different magnetic structures.…”

Magnetic phase diagram of the solid solution LaMn2(Ge1−xSix)2 (0 ≤ x ≤ 1) unraveled by powder neutron diffraction

“…The wide range of behavior exhibited by the RE Mn 2 X 2 materials is related to the rich diversity of collinear and non-collinear magnetic states that can be realized in this atomic arrangement 15 – 26 . Magnetic ordering temperatures between 300 and 714 K have been observed for all compounds of this type 1 , 27 , and many of them undergo several magnetic transitions upon cooling before they reach their magnetic ground state. Previous studies on various solid solutions based on RE Mn 2 X 2 indicated that the Mn–Mn distances play a major role in the formation of different magnetic structures.…”