Unconventional magnetic glassiness in non-centrosymmetric Sm$_7$Pd$_3$: Interplay of magnetic frustration, long-range order, and frozen domains

TL;DR

This study uncovers complex magnetic behaviors in Sm$_7$Pd$_3$, including spin glass, domain glass, and ferromagnetism, driven by competing interactions and crystal field effects, revealing unconventional magnetic glassiness in a non-centrosymmetric material.

Contribution

It provides a detailed experimental analysis of the coexistence of multiple magnetic states and their origins in Sm$_7$Pd$_3$, highlighting the interplay of frustration, long-range order, and domain freezing.

Findings

Presence of spin glass, domain glass, and ferromagnetic behaviors.

Large coercivity indicating ferromagnetic domains below T_C.

Evidence of competing FM and AFM interactions from magnetization data.

Abstract

We present a comprehensive investigation of the intricate spin dynamics in the non-centrosymmetric compound Sm$_7$Pd$_3$, revealing the coexistence of spin glass, domain glass, and ferromagnetic (FM) behaviors. Magnetic field-dependent measurements indicate large coercivity, suggesting ferromagnetic domain formation below the Curie temperature ($T_C \sim 173$ K), while temperature-dependent magnetization data point to antiferromagnetic (AFM) coupling, highlighting the competition between FM and AFM interactions. Detailed ac susceptibility, isothermal remanent magnetization, and aging effect measurements demonstrate the presence of two distinct types of glassiness in the sample, and their possible origins are discussed extensively. Magnetization measurements reveal the mixing of the J = 5/2 ground state of Sm$^{3+}$ with the excited J = 7/2 multiplet, lying 965 K above. The specific heat data show further crystalline electric field splitting of the J = 5/2 state into a ground-state doublet and a fourfold-degenerate excited state.