Dominant ferromagnetism in the spin-1/2 half-twist ladder 334 compounds, Ba3Cu3In4O12 and Ba3Cu3Sc4O12

TL;DR

This study investigates the magnetic properties of Ba3Cu3In4O12 and Ba3Cu3Sc4O12, revealing dominant ferromagnetic interactions and complex antiferromagnetic ordering in their half-twist ladder structures, contributing to understanding low-dimensional magnetic systems.

Contribution

It introduces the magnetic behavior of 334 compounds with half-twist ladders, highlighting ferromagnetic interactions and complex phase diagrams, which are novel insights for this class of materials.

Findings

Presence of significant ferromagnetic interactions along Cu ladders.

Observation of 3D antiferromagnetic ordering below 20 K.

Complex magnetic phase diagram with three regimes under magnetic field.

Abstract

The magnetic properties of polycrystalline samples of Ba3Cu3In4O12 (In-334) and Ba3Cu3Sc4O12 (Sc-334) are reported. Both 334 phases have a structure derived from perovskite, with CuO4 squares interconnected to form half-twist ladders along the c-axis. The Cu-O-Cu angles, ~ 90o, and the positive Weiss temperatures indicate the presence of significant ferromagnetic (FM) interactions along the Cu ladders. At low temperatures, T < 20 K, sharp transitions in the magnetic susceptibility and heat capacity measurements indicate three-dimensional (3D) antiferromagnetic (AFM) ordering at TN. TN is suppressed on application of a field and a complex magnetic phase diagram with three distinct magnetic regimes below the upper critical field can be inferred from our measurements. The magnetic interactions are discussed in relation to a modified spin-1/2 FM-AFM model and the 334 half-twist ladder is compared to other 2-rung ladder spin-1/2 systems.