Magnetic structure of Yb2Pt2Pb: Ising moments on the Shastry-Sutherland Lattice

TL;DR

This study reveals the magnetic structure of Yb2Pt2Pb, showing Ising moments on the Shastry-Sutherland lattice with orthogonal stripe order, and demonstrates the moments' Ising nature through field suppression experiments.

Contribution

It provides the first detailed neutron diffraction analysis of Yb2Pt2Pb's magnetic structure, highlighting the Ising character and complex stripe order on the SSL.

Findings

Yb2Pt2Pb orders antiferromagnetically at 2.07 K.

Magnetic structure involves orthogonal stripe order with moments perpendicular to dimers.

Magnetic moments exhibit Ising behavior, unaffected by fields along certain directions.

Abstract

Neutron diffraction measurements were carried out on single crystals and powders of Yb2Pt2Pb, where Yb moments form planes of orthogonal dimers in the frustrated Shastry-Sutherland Lattice (SSL). Yb2Pt2Pb orders antiferromagnetically at TN=2.07 K, and the magnetic structure determined from these measurements features the interleaving of two orthogonal sublattices into a 5*5*1 magnetic supercell that is based on stripes with moments perpendicular to the dimer bonds, which are along (110) and (-110). Magnetic fields applied along (110) or (-110) suppress the antiferromagnetic peaks from an individual sublattice, but leave the orthogonal sublattice unaffected, evidence for the Ising character of the Yb moments in Yb2Pt2Pb. Specific heat, magnetic susceptibility, and electrical resistivity measurements concur with neutron elastic scattering results that the longitudinal critical fluctuations are gapped with E about 0.07 meV.