Intertwined Magnetic Sub-Lattices in the Double Perovskite Compound LaSrNiReO6

TL;DR

This study uses muon spin rotation to reveal a complex, long-range magnetic order in LaSrNiReO6, challenging previous spin glass assumptions and identifying three distinct magnetic phases across a wide temperature range.

Contribution

It provides the first detailed magnetic ground state analysis of LaSrNiReO6, demonstrating the presence of intertwined magnetic lattices and multiple magnetic phases.

Findings

Long-range dynamically ordered ground state below 23 K

Identification of three magnetic phases between 23 K and 300 K

Evidence of intertwined magnetic lattices within the double perovskite structure

Abstract

We report a muon spin rotation ($\mu^{+}$SR) study of the magnetic properties of the double perovskite compound LaSrNiReO$_{6}$. Using the unique length and time scales of the $\mu^{+}$SR technique, we successfully clarify the magnetic ground state of LaSrNiReO$_{6}$, which was previously deemed as a spin glass state. Instead, our $\mu^{+}$SR results point towards a long-range dynamically ordered ground state below $T_{\rm C}= 23$ K, for which a static limit is foreseen at $T=0$. Furthermore, between 23 K$<T\leq$300 K, three different magnetic phases are identified: a dense ($23$ K$<T\leq75$ K), a dilute ($75$ K$<T\leq250$ K), and a paramagnetic ($T>250$ K) state. Our results reveal how two separate, yet intertwined magnetic lattices interact within the unique double perovskite structure and the importance of using complementary experimental techniques to obtain a complete understanding of the microscopic magnetic properties of complex materials.