[{"type":"article-journal","title":"Restoration of quantum critical behavior by disorder in pressure-tuned (Mn,Fe)Si","issued":{"date-parts":[["2017"]]},"volume":"2","issue":"1","page":"44","container-title":"npj Quantum Materials","DOI":"10.1038\/s41535-017-0049-0","author":[{"family":"Goko","given":"Tatsuo"},{"family":"Arguello","given":"Carlos J."},{"family":"Hamann","given":"Andreas"},{"family":"Wolf","given":"Thomas"},{"family":"Lee","given":"Minhyea"},{"family":"Reznik","given":"Dmitry"},{"family":"Maisuradze","given":"Alexander"},{"family":"Khasanov","given":"Rustem"},{"family":"Morenzoni","given":"Elvezio"},{"family":"Uemura","given":"Yasutomo J."}],"ISSN":"2397-4648","abstract":"In second-order quantum phase transitions from magnetically ordered to paramagnetic states at T\u2009=\u20090, tuned by pressure or chemical substitution, a quantum critical point is expected to appear with critical behavior manifesting in the slowing down of spin fluctuations in the paramagnetic state and a continuous development of the order parameter in the ordered state. Quantum criticality is discussed widely as a possible driving force for unconventional superconductivity and other exotic phenomena in correlated electron systems. In the real world, however, quantum critical points and quantum criticality are often masked by a preceding first-order transition and\/or the development of competing states. Pressure tuning of the itinerant-electron helical magnet MnSi is a well-known example of the suppression of a quantum critical point due to a first-order phase transition and resulting destruction of the ordered state. Utilizing muon spin relaxation experiments, here we report that 15% Fe-substituted (Mn,Fe)Si exhibits completely different behavior with pressure tuning, including the restoration of second-order quantum critical behavior and a quantum critical point at p QPC \u2009~\u200921\u201323\u2009kbar, which coincides with the T\u2009=\u20090 crossing point of the extrapolated phase boundary line of pure MnSi. This result is quantitatively consistent with the recent theory of itinerant-electron ferromagnets by Sang, Belitz, and Kirkpatrick, who argued that disorder would restore a quantum critical point which is otherwise hidden by a first-order transition.","kit-publication-id":"1000073874"}]