Structural trends and itinerant magnetism of the new cage-structured compound HfMn₂Zn₂₀

Abstract

A new cage-structured compound – HfMn2Zn20 – belonging to the AB 2 C 20 (A, B = transition or rare earth metals, and C = Al, Zn, or Cd) family of structures has been synthesized via the self-flux method. The new compound crystallizes in the space group Fd-3m with lattice parameter a ≈ 14.0543(2) Å (Z = 8) and exhibits non-stoichiometry due to Mn/Zn mixing on the Mn-site and an underoccupied Hf-site. The structure refines to Hf0.93Mn1.63Zn20.37 and follows lattice size trends when compared to other HfM 2Zn20 (M = Fe, Co, and Ni) structures. The magnetic measurements show that this compound displays a modified Curie-Weiss behavior with a transition temperature around 22 K. The magnetization shows no saturation, a small magnetic moment, and near negligible hysteresis, all signs of itinerant magnetism. The Rhodes-Wohlfarth ratio and the spin fluctuation parameters ratio both confirm the itinerant nature of the magnetism in HfMn2Zn20.