Physical properties of intergrowth compound Eu2CuZn2 P3

The physical properties of single-crystalline Eu2CuZn2P3 were inspected via thermodynamic, transport, and neutron diffraction measurements. Eu2CuZn2P3 is composed of EuCuP and EuZn2P2 motifs stacked in a one-to-one ratio. The magnetic response of Eu2CuZn2P3 is similar to that of EuZn2P2 in its A-type antiferromagnetic (semiconducting) state. A Néel temperature of TN=40.3K is obtained from the specific heat capacity. Single-crystal neutron diffraction reveals a (001) magnetic propagation vector, with primarily in-plane moments coupled along [001] in an up-up-down-down pattern. This spin structure retains the ferromagnetic EuCuP motifs and antiferromagnetic coupling across the EuZn2P2 motifs. The electrical resistivity is characterized by metallic behavior above 100 K, an increase in ρ upon cooling below ≈75K, and a large negative magnetoresistance below TN. First principles calculations evidence a narrow band gap for antiferromagnetic ordering and semimetallic behavior for the ferromagnetic state. This is consistent with the observed effect of magnetic field on the electrical resistivity. Hall effect measurements reveal a field-induced, negative anomalous Hall effect that increases on cooling down to 2 K. Also, an unconventional contribution to the Hall effect dominates the low-field Hall signal, particularly near TN, and is similar in appearance to a topological Hall effect. However, further work is necessary to understand if any of the transport properties have topological origins or if magnetism-induced modifications to the Fermi surface induce these unusual Hall effect signals in this and related materials.