Multiple Magnetic Transitions in the Trilayer Nickelate Pr$_4$Ni$_3$O$_{10}$ Revealed by Muon-Spin Rotation

TL;DR

This study uses muon-spin rotation to investigate magnetic phase transitions in Pr4Ni3O10, revealing three distinct magnetic transitions, their behavior under pressure, and the suppression of magnetic order with increasing pressure.

Contribution

It provides the first detailed muon-spin rotation analysis of Pr4Ni3O10, identifying multiple magnetic transitions and their evolution under hydrostatic pressure.

Findings

Identified three magnetic transitions at specific temperatures.

Observed suppression of magnetic order and Ni magnetic moment under pressure.

Revealed weakly first-order-like behavior of the high-temperature transition.

Abstract

A muon-spin rotation/relaxation ($\mu$SR) study of the trilayer Ruddlesden--Popper nickelate Pr$_4$Ni$_3$O$_{10}$ was performed at ambient pressure and under hydrostatic pressure up to 2.2 GPa. Three magnetic transitions were identified at ambient pressure: the onset of spin-density-wave (SDW) order at $T_{\rm SDW} \simeq 158$ K, an intermediate-temperature transition at $T^{\ast} \simeq 90$--100 K, and a low-temperature transition at $T_{\rm SDW}^{\rm Pr} \simeq 25$--27 K. While the intermediate transition at $T^{\ast}$ induces only minor changes in the internal-field distribution, the transition at $T_{\rm SDW}^{\rm Pr}$ is accompanied by a pronounced reconstruction of the magnetic structure, consistent with previous reports attributing enhanced interlayer coherence to the ordering of the Pr sublattice. The high-temperature transition at $T_{\rm SDW}$ is characterized by the sharp development of static internal magnetic fields with a narrow transition width of $0.65(4)$ K. Weak-transverse-field measurements reveal a finite thermal hysteresis of $0.27(6)$ K, with $T_{\rm SDW}^{\rm warming} > T_{\rm SDW}^{\rm cooling}$, indicating weakly first-order-like behavior. Hydrostatic pressure suppresses $T_{\rm SDW}$ linearly and reduces the ordered Ni magnetic moment $M$, with corresponding rates of ${\rm d}T_{\rm SDW}/{\rm d}p = -4.9(1)$ K/GPa and ${\rm d}\ln M/{\rm d}p = -2.0(5)\times10^{-2}$ GPa$^{-1}$, respectively, thereby demonstrating a gradual weakening of the spin-density-wave instability under compression.