인문학
사회과학
자연과학
공학
의약학
농수해양학
예술체육학
복합학
지원사업
학술연구/단체지원/교육 등 연구자 활동을 지속하도록 DBpia가 지원하고 있어요.
커뮤니티
연구자들이 자신의 연구와 전문성을 널리 알리고, 새로운 협력의 기회를 만들 수 있는 네트워킹 공간이에요.
초록·키워드
Magnetic transition in nonmetals requires the presence of a considerable proportion of magnetic spins. A new type of ferromagnet named dilute ferromagnetism that contradicts this well-established concept is proposed for semiconductors of ZnO etc. but has remained experimentally unproven. In this study, an unconventional superlong-range magnetic coupling and ferromagnetic spin freezing are reported, which can be viewed as an experimental realization of an intrinsic dilute ferromagnetism, in mechanoluminescent material of Eu<sub>x</sub>Sr<sub>1-</sub> <sub>x</sub>Al<sub>2</sub>O<sub>4</sub> (x = 0.2-2%), wherein Eu is sparsely incorporated into the lattice to substitute Sr. Ferromagnetic coupling appears below ≈80 K and fully saturated ferromagnetic magnetization appears below ≈3 K, with an unusually large magnetic moment of ≈14 µ<sub>B</sub> per Eu<sup>2+</sup>. Muon spin spectroscopy demonstrates intrinsic spin freezing with a spontaneous internal field developed below T<sub>C</sub> of ≈3 K. The neighboring magnetic Eu<sup>2+</sup> ions in the lattice have an exceptionally large separation more than one order of magnitude larger than those in conventional magnets, marking it as a unconventional magnetic order over a superlong distance. Bound magnetic polarons arising from electrons trapped at oxygen vacancies may account for this unconventional ferromagnetism. Magnetization under light radiation supports this scenario.
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오류를 발견하셨다면 해당 부분을 드래그한 후 ' 를 통해 신고해주세요.
오류를 발견하셨다면 해당 부분을 드래그한 후 ' 를 통해 신고해주세요.