Muon Spin Relaxation and Neutron Diffraction Studies of Cluster-Glass States in Sr1-xLaxRuO3

TL;DR

This study investigates the magnetic evolution in Sr1-xLaxRuO3, revealing that cluster-glass states gradually transform into long-range ferromagnetic order with decreasing temperature, challenging conventional transition models.

Contribution

It provides detailed muSR and neutron diffraction evidence showing the development of magnetic order in Sr1-xLaxRuO3, highlighting a non-standard transition process.

Findings

Magnetic clusters develop above T^* without anomalies.

Volume fraction of magnetic order reaches nearly 100% at low temperatures.

Ground state for x=0.3 is long-range ferromagnetic order.

Abstract

To clarify the magnetic properties of cluster-glass states in Sr1-xLaxRuO3 (0.3 <= x <= 0.5), we report herein the results of muon spin relaxation (muSR) and neutron powder diffraction measurements. The muSR experiments showed that magnetic clusters start developing well above the peak temperature T^* in the ac susceptibility. The volume fraction of the magnetically ordered region increases continuously with decreasing temperature, showing no anomaly at T^*, and reaches nearly 100% at the lowest temperature. The temperature variation of the volume fraction is essentially independent of the La concentration in the x range presently investigated, although the dc magnetization is significantly suppressed with increasing x. Neutron powder diffraction experiments revealed that the ground state for x = 0.3 is a long-range ferromagnetic ordered state. These results indicate that, with decreasing temperature, cluster-glass states in Sr1-xLaxRuO3 gradually develop into long-range ferromagnetic ordered states with decreasing temperature, and that the magnetic ordering process differs strikingly from that expected for a conventional second-order ferromagnetic transition.