Muon spin relaxation and susceptibility measurements of an itinerant-electronsystem Sr1-xCaxRuO3: Quantum evolution from ferromagnet to paramagnet

Article

关键词: MAGNETIC-PROPERTIES;    TRANSITION-TEMPERATURE;    MOTT TRANSITION;    CARUO3;    SRRUO3;    FLUCTUATIONS;    MNSI;    METALS;    PHASE;    SR1-XCA(X)RUO3;   

DOI  :  10.1103/PhysRevB.84.224415

来源: SCIE

【 摘 要 】

Muon spin relaxation (mu SR) and magnetic susceptibility measurements have been performed in the itinerant-electron magnet Sr1-xCaxRuO3, with x = 0.0, 0.3, 0.5, 0.65, 0.7, 0.75, 0.8, 0.9, and 1.0. SrRuO3 is a ferromagnet with the critical temperature T-c similar to 160 K. Upon (Sr, Ca) substitution, T-c decreases monotonically with increasing Ca concentration x and the ferromagnetic order disappears around x = 0.7. Very weak static magnetism is observed in the x = 0.75 and 0.8 systems, while the x = 0.9 and 1.0 systems remain paramagnetic in their full volume. Phase separation between volumes with and without static magnetism was observed in the x = 0.65, 0.7, 0.75, and 0.8 systems, near the magnetic crossover around x = 0.7. In this concentration region, mu SR measurements revealed discontinuous evolution of magnetic properties in contrast to magnetization measurements, which exhibit seemingly continuous evolution. Unlike the volume-integrated magnetization measurements, mu SR can separate the effects of the ordered moment size and the volume fraction of magnetically ordered regions. The muon spin relaxation rate 1/T-1 exhibits critical slowing down of spin fluctuations near T-c in the ferromagnetic systems with x = 0.0-0.65, consistent with the behavior expected in the self-consistent renormalization theory of itinerant electron ferromagnets. The lack of maximum of 1/T-1 in the x = 0.7 system indicates the disappearance of critical slowing down. These results demonstrate a first-order quantum evolution in the ferromagnet to paramagnet crossover near x = 0.7.

【 授权许可】

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