Complex magnetic properties in the mixed 4f -5d double perovskite iridates Ln2ZnIrO6 (Ln = Nd, Sm, Eu & Gd)

M. Vogl; R. Morrow; A. A. Aczel; R. Beltran Rodriguez; A. U. B. Wolter; S. Wurmehl; S. Aswartham; B. Büchner

doi:10.1103/PhysRevMaterials.4.054413

paper

Complex magnetic properties in the mixed 4f -5d double perovskite iridates Ln2ZnIrO6 (Ln = Nd, Sm, Eu & Gd)

arXiv:1910.13552 · doi:10.1103/PhysRevMaterials.4.054413

Abstract

In this work, we report on the synthesis and magnetic properties of a series of double perovskites Ln $_{2}$ ZnIrO $_{6}$ with Ln = Nd, Sm, Eu & Gd. These compounds present new examples of the rare case of double perovskites (general formula A $_{2}$ BB'O $_{6}$ ) with a magnetic 4f -ion on the A-site in combination with the strongly spin-orbit coupled 5d-transition metal ion Ir $^{4 +}$ on the B-sublattice. We discuss the impact of different rare earths on the macroscopic magnetic properties. Gd $_{2}$ ZnIrO $_{6}$ and Eu $_{2}$ ZnIrO $_{6}$ show weak canted antiferromagnetic order below T $_{N}$ = 23 K and T $_{N}$ = 12 K, respectively. Sm $_{2}$ ZnIrO $_{6}$ orders antiferromagnetically at T $_{N}$ = 13 K. Nd $_{2}$ ZnIrO $_{6}$ exhibits complex magnetic properties with strong field dependence ranging from a two-step behavior at H = 0.01 T to an antiferromagnetic ground state at intermediate external fields and a spin-flop phase at H $\geq$ 4 T, which suggests complex interplay between Nd $^{3 +}$ and Ir $^{4 +}$ . To further shed light on this magnetic interaction, the magnetic structure of Nd $_{2}$ ZnIrO $_{6}$ 's ground state is examined via neutron powder diffraction.