A Novel Class of High-TC Ferromagnetic Semiconductors: Novel Ferromagnetic Semiconductors

Author

Shlyk, L.V. ; Kryukov, S.A. ; De Long, L.E. ; Schupp-Niewa, B. ; Niewa, R. ; Lynn, J.W. ; Huang, Qing ; Arenholz, E. ; Piamonteze, C.

Author_Institution

Dept. of Phys. & Astron., Kentucky Univ., Lexington, KY

fYear

2008

fDate

13-16 July 2008

Firstpage

142

Lastpage

147

Abstract

We have grown single crystals of novel ruthenates (Sr,Ba)(Fe,Co)_2+xRu_4-xO₁₁ 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 P6₃/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.

Keywords

Hall effect; X-ray absorption; X-ray chemical analysis; X-ray diffraction; band structure; barium compounds; cobalt compounds; crystal growth; electrical resistivity; galvanomagnetic effects; iron compounds; magnetic circular dichroism; magnetic moments; neutron diffraction; semimagnetic semiconductors; space groups; strontium compounds; (SrBa)(FeCo)_2+xRu_4-xO₁₁; EDX; R-type hexagonal ferrite structure; X-ray absorption; X-ray diffraction; X-ray magnetic circular dichroism; anomalous Hall conductance; chemical substitution; dilute magnetic semiconductors; electrical resistivity; electronic structure; high-T_C ferromagnetic semiconductors; magnetic moment; magnetotransport; narrow-gap semiconductor; neutron diffraction; ruthenates; single crystal growth; space group P6₃/mmc; spintronic applications; Chemical elements; Conductivity; Crystals; Electromagnetic wave absorption; Magnetic semiconductors; Magnetoelectronics; Neutrons; Semiconductivity; Temperature; X-ray diffraction;

fLanguage

English

Publisher

ieee

Conference_Titel

University/Government/Industry Micro/Nano Symposium, 2008. UGIM 2008. 17th Biennial

Conference_Location

Louisville, KY

Print_ISBN

978-1-4244-2484-9

Electronic_ISBN

978-1-4244-2485-6

Type

conf

DOI

10.1109/UGIM.2008.45

Filename

4573223