Chemically substituted SrRuO3 provides a versatile platform for studying the relationships between itinerant ferromagnetism and quantum criticality. Substituting Sr with Ca suppressed ferromagnetic phase while also suggested an evolution of ferromagnetic quantum critical fluctuations originating from itinerant spins. The thermal and magnetic investigations for the isoelectronic doped compound Sr1-x(La0.5K0.5)xRuO3 demonstrate that in contrast to the Ca-doped compound, increasing La and K concentrations strongly suppresses quantum spin fluctuations, and cluster-glass state starts developing at the critical doping region x~0.5. The difference of the spin states in the ferromagnetic critical regions between those compounds can be understood by the combination of local correlated disorder effect and the small coherence of itinerant Ru 4d electrons.
The article regarding this work:
R. Iwahara, R. Sugawara, Rahmanto, Y. Honma, K. Matsuoka, A. Matsuo, K. Kindo, K. Tenya, and M. Yokoyama:
"Avoided quantum criticality and cluster-glass formation in itinerant ferromagnet Sr1-x(La0.5K0.5)xRuO3",
Physical Review Materials 4, 074404-1-8 (2020).
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