Novel Class of High-T(sub C) Ferromagnetic Semiconductors.

Shlyk, L. V. ; Kryukov, S. A. ; De Long, L. E. ; Schuepp-Niewa, B. ; Niewa, R. ; Lynn, J. W.

Technical Information Center Oak Ridge Tennessee

关键词: Semiconductors;    Absorption;    Electronic structure;    Magnetic moments;    Monocrystals;   

RP-ID  :  DE2008941708

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

We have grown single crystals of novel ruthenates (Sr,Ba)(Fe,Co)(sub 2+x)Ru(sub 4-x)O(sub 11) that exhibit long-range ferromagnetic order well above room temperature, accompanied by narrow-gap semiconducting properties that include a large anomalous Hall conductance, low resistivity, high carrier concentration and low coercive field, which are properties well suited to spintronic applications. X-ray diffraction, EDX, neutron diffraction and x-ray absorption measurements on single crystals firmly establish the 'R-Type' hexagonal ferrite structure (space group P6(sub 3)/mmc, No 194) and single-phase nature of all samples. The electronic structure and physical properties can be tuned by simple chemical substitution of two elements, M = Fe or Co, or by varying the relative concentration of 3d solutes and 4d Ru. Our magnetotransport, x-ray magnetic circular dichroism and magnetic moment data suggest the mechanism for FM order is quite different from that governing known dilute magnetic semiconductors.