Large magnetoresistance in intermetallic compounds R2Mn3Si5 (R = Tb, Dy and Ho)

TL;DR

This study investigates the magnetic and magnetoresistive properties of R2Mn3Si5 (R=Tb, Dy, Ho) compounds, revealing large negative magnetoresistance near magnetic transition temperatures due to spin-dependent scattering and layered structure effects.

Contribution

It reports the discovery of giant negative magnetoresistance in R2Mn3Si5 compounds and elucidates its origin related to magnetic ordering and layered structure.

Findings

Large negative MR (~50%) near TC2 at 9 T

Distinct magnetic ordering temperatures for Mn and R moments

Magnetoresistance attributed to spin-dependent scattering and exchange interactions

Abstract

Magnetization (M) and magnetoresistance (MR) measurements on polycrystalline R2Mn3Si5 (R = Tb, Dy and Ho) compounds (tetragonal, space group P4/mnc) have been carried out in the temperature range of 2 K-300 K, in various applied fields. Both, the rare earth and the Mn, are found to carry magnetic moments in these compounds. Mn has two sub-lattices (Mn1 and Mn2) that order magnetically at two different temperatures. Rare earth and Mn1 moments order ferromagnetically at TC1 whereas Mn2 is found to magnetically order at TC2 (TC1 = 89 K, 86 K, 78 K and TC2 = 18 K, 34 K, 16 K for R = Tb, Dy and Ho compounds, respectively). Magnetoresistance measurements reveal large negative MR values of about 50 % near TC2 at 9 T in all these compounds. This giant magnetoresistance is attributed to the spin-dependent scattering effects, competing exchange interactions and the layered structure of these compounds