Magnetic Transitions under Ultrahigh Magnetic Fields of up to 130 T in the Breathing Pyrochlore Antiferromagnet LiInCr4O8

TL;DR

This study investigates the magnetic behavior of the breathing pyrochlore antiferromagnet LiInCr4O8 under ultrahigh magnetic fields up to 130 T, revealing a half magnetization plateau and evidence of a spin gap, highlighting strong spin-lattice coupling.

Contribution

It provides the first detailed high-field magnetization data for breathing pyrochlore antiferromagnets, demonstrating unique frustrated magnetic states with strong spin-lattice interactions.

Findings

Observation of a half magnetization plateau above 90 T

Identification of a 2.2 meV spin gap in LiGa0.125In0.875Cr4O8

Strong spin-lattice coupling in the breathing pyrochlore system

Abstract

The magnetization processes of the spin-3/2 antiferromagnet LiInCr4O8 comprising a "breathing" pyrochlore lattice, which is an alternating array of small and large tetrahedra, are studied under ultrahigh magnetic fields of up to 130 T using state-of-the-art pulsed magnets. A half magnetization plateau is observed above 90 T to 130 T, suggesting that LiInCr4O8 has a strong spin-lattice coupling, similar to conventional chromium spinel oxides. The magnetization of LiGa0.125In0.875Cr4O8, in which the structural and magnetic transitions at low temperatures have been completely suppressed, shows a sudden increase above 13 T, indicating that a spin gap of 2.2 meV exists between a tetramer singlet ground state and an excited state with total spin 1, with the latter being stabilized by the application of a magnetic field. The breathing pyrochlore antiferromagnet is found to be a unique frustrated system with strong spin-lattice coupling and bond alternation.